Update docs

This commit is contained in:
aaron 2024-11-04 23:18:04 +00:00
parent 94add5d452
commit a3cc2dfbda
30 changed files with 850 additions and 770 deletions

View file

@ -34,7 +34,7 @@ export default withMermaid({
items: [ items: [
{ text: "Reactivity: Core", link: "/api/reactivity-core" }, { text: "Reactivity: Core", link: "/api/reactivity-core" },
{ text: "Reactivity: Utility", link: "/api/reactivity-utility" }, { text: "Reactivity: Utility", link: "/api/reactivity-utility" },
{ text: "Reactivity: Control Flow", link: "/api/reactivity-flow" }, { text: "Reactivity: Dynamic Scoping", link: "/api/reactivity-dynamic" },
{ text: "Element Creation", link: "/api/creation" }, { text: "Element Creation", link: "/api/creation" },
{ text: "Animation", link: "/api/animation" }, { text: "Animation", link: "/api/animation" },
{ text: "Strict Mode", link: "/api/strict-mode" }, { text: "Strict Mode", link: "/api/strict-mode" },
@ -52,20 +52,25 @@ export default withMermaid({
{ text: "Sources", link: "/tut/crash-course/4-source" }, { text: "Sources", link: "/tut/crash-course/4-source" },
{ text: "Effects", link: "/tut/crash-course/5-effect" }, { text: "Effects", link: "/tut/crash-course/5-effect" },
{ text: "Scopes", link: "/tut/crash-course/6-scope" }, { text: "Scopes", link: "/tut/crash-course/6-scope" },
{ text: "Stateful Components", link: "/tut/crash-course/7-stateful-component" }, { text: "Reactive Components", link: "/tut/crash-course/7-reactive-component" },
{ text: "Implicit Effects", link: "/tut/crash-course/8-implicit-effect" }, { text: "Implicit Effects", link: "/tut/crash-course/8-implicit-effect" },
{ text: "Derived Sources", link: "/tut/crash-course/9-derived-source" }, { text: "Derived Sources", link: "/tut/crash-course/9-derived-source" },
{ text: "Cleanup", link: "/tut/crash-course/10-cleanup" }, { text: "Cleanup", link: "/tut/crash-course/10-cleanup" },
{ text: "Control Flow", link: "/tut/crash-course/11-control-flow" }, { text: "Dynamic Scoping", link: "/tut/crash-course/11-dynamic-scope" },
{ text: "Actions", link: "/tut/crash-course/12-actions" }, { text: "Actions", link: "/tut/crash-course/12-actions" },
{ text: "Strict Mode", link: "/tut/crash-course/13-strict-mode" }, { text: "Strict Mode", link: "/tut/crash-course/13-strict-mode" },
{ text: "Concepts Summary", link: "/tut/crash-course/14-concepts" } { text: "Concepts Summary", link: "/tut/crash-course/14-concepts" }
] ]
}, },
{ {
text: "Advanced Reactivity", text: "Dynamic Scoping",
items: [
{ text: "Custom Scopes", link: "/tut/dynamic-scoping/custom"}
]
},
{
text: "Design Patterns",
items: [ items: [
{ text: "Nested Scopes", link: "/tut/advanced/nested-scoping.md"}
] ]
} }
], ],

View file

@ -17,3 +17,9 @@
margin-top: auto !important; margin-top: auto !important;
margin-bottom: auto !important; margin-bottom: auto !important;
} }
.VPBadge a {
text-decoration: none;
color: inherit
}

View file

@ -1,7 +1,7 @@
// .vitepress/theme/index.js // .vitepress/theme/index.js
import DefaultTheme from 'vitepress/theme' import DefaultTheme from 'vitepress/theme'
import './vars.css' import './vars.css'
import './home.css' import './index.css'
export default { export default {
extends: DefaultTheme, extends: DefaultTheme,

View file

@ -31,6 +31,11 @@
--vp-c-divider: #dfe2e6; --vp-c-divider: #dfe2e6;
--vp-c-gutter: #dfe2e6; --vp-c-gutter: #dfe2e6;
--vp-plugin-tabs-tab-bg: var(--vp-c-bg); --vp-plugin-tabs-tab-bg: var(--vp-c-bg);
--vp-badge-info-bg: #122d26;
--vp-badge-info-text: #6bdbbd;
--vp-badge-tip-bg: #132741;
--vp-badge-tip-text: #70abfa;
} }
.dark { .dark {
@ -44,3 +49,4 @@
--vp-c-divider: #1d273c; --vp-c-divider: #1d273c;
--vp-c-gutter: #181d27; --vp-c-gutter: #181d27;
} }

View file

@ -1,6 +1,6 @@
# Animation API # Animation
## spring() ## spring() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Returns a new source with a value always moving torwards the input source value. Returns a new source with a value always moving torwards the input source value.
@ -18,8 +18,7 @@ Returns a new source with a value always moving torwards the input source value.
- **Details** - **Details**
An effect is created to update the new source every frame based on the input Creates a reactive scope internally to detect source updates.
source value.
The movement is physically simulated according to a The movement is physically simulated according to a
[spring](https://en.wikipedia.org/wiki/Simple_harmonic_motion). [spring](https://en.wikipedia.org/wiki/Simple_harmonic_motion).
@ -39,3 +38,7 @@ Returns a new source with a value always moving torwards the input source value.
You can change when the solver runs by calling `vide.step(dt)`, which will You can change when the solver runs by calling `vide.step(dt)`, which will
advance the simulation time by `dt` seconds and automatically stop the advance the simulation time by `dt` seconds and automatically stop the
solver running in heartbeat. solver running in heartbeat.
::: warning
Large periods or damping ratios can break the spring.
:::

View file

@ -1,39 +1,4 @@
# Element Creation API # Element Creation
<br/>
## mount()
Runs a function in a new stable scope and optionally applies its result to a
target instance.
- **Type**
```luau
function mount<T>(component: () -> T, target: Instance?): () -> ()
```
- **Details**
The result of the function is applied to a target in the same way
properties are using `create()`.
The function is ran in a new stable scope, just like
[root()](reactivity-core.md#root).
Returns a function that when called will destroy the stable scope.
- **Example**
```luau
local function App()
return create "ScreenGui" {
create "TextLabel" { Text = "Vide" }
}
end
mount(App, game.StarterGui)
```
## create() ## create()
@ -45,7 +10,7 @@ Creates a new UI element, applying any given properties.
function create(class: string): (Properties) -> Instance function create(class: string): (Properties) -> Instance
function create(instance: Instance): (Properties) -> Instance function create(instance: Instance): (Properties) -> Instance
type Properties = Map<string|number, any> type Properties = Map<string|number, unknown>
``` ```
- **Details** - **Details**
@ -77,42 +42,22 @@ Creates a new UI element, applying any given properties.
Basic element creation. Basic element creation.
```luau ```luau
local frame = create "Frame" { local frame = create "TextButton" {
Name = "NewFrame", Name = "Button",
Position = UDim2.fromScale(1, 0) Size = UDim2.fromOffset(200, 160),
Activated = function()
print "clicked"
end,
create "UICorner" {}
} }
``` ```
A component using property nesting.
```luau
type Layout = {
Layout = {
Position: UDim2?,
Size: UDim2?,
AnchorPoint: Vector2?
}
}
type Children = {
Children = Array<Instance>
}
function Background(props: Layout & Children & {
Color: Color3
})
return create "Frame" {
BackgroundColor3 = props.Color,
props.Layout,
props.Children
}
end
```
## action() ## action()
Creates a callback that can be passed to `create()` to invoke custom actions on Creates a special object that can be passed to `create()` to invoke custom
instances. actions on instances.
- **Type** - **Type**
@ -122,27 +67,27 @@ instances.
- **Details** - **Details**
When passed to `create()`, the given callback is called with the instance When passed to `create()`, the function is called with the instance being
being created as the only argument. Actions take precedence over property created as the only argument. Actions take precedence over property and
and child assignments. child assignments.
A priority can be optionally specified to ensure certain actions run after A priority can be optionally specified to ensure certain actions run after
other actions. Higher priority numbers are ran after lower priority numbers. other actions. Lower priority values are ran first.
- **Example** - **Example**
An action to listen to changed properties: An action to listen to changed properties:
```luau ```luau
local function changed(property: string, callback: (new) -> ()) local function changed(property: string, fn: (new) -> ())
return action(function(instance) return action(function(instance)
local con - instance:GetPropertyChangedSignal(property):Connect(function() local cn = instance:GetPropertyChangedSignal(property):Connect(function()
callback(instance[property]) fn(instance[property])
end) end)
-- disconnect on reactive scope destruction to allow gc of instance -- disconnect on scope destruction to allow gc of instance
cleanup(function() cleanup(function()
con:Disconnect() cn:Disconnect()
end) end)
end) end)
end end
@ -150,7 +95,7 @@ instances.
local output = source "" local output = source ""
create "TextBox" { create "TextBox" {
-- will update the `output` source anytime the text property is changed -- will update the output source anytime the text property is changed
changed("Text", output) changed("Text", output)
} }
``` ```
@ -162,15 +107,46 @@ A wrapper for `action()` to listen for property changes.
- **Type** - **Type**
```luau ```luau
function changed(property: string, callback: (...unknown) -> ()): Action function changed(property: string, fn: (unknown) -> ()): Action
``` ```
- **Details** - **Details**
Will run the given callback any time the property is changed, as well as Will run the given function immediately and whenever the property updates.
when the action is initially run.
The changed connection is disconnected when the scope the action is ran in The function is called with the updated property value.
is destroyed.
Runs with an action priority of 1. Runs with an action priority of 1.
## mount() <Badge type="info" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">STABLE</a></Badge>
Runs a function in a new stable scope and optionally applies its result to a
target instance.
- **Type**
```luau
function mount<T>(component: () -> T, target: Instance?): () -> ()
```
- **Details**
This is a utility for `root()` when parenting a component to an existing
instance.
The result of the function is applied to a target in the same way
properties are using `create()`.
Returns a function that when called will destroy the stable scope.
- **Example**
```luau
local function App()
return create "ScreenGui" {
create "TextLabel" { Text = "Vide" }
}
end
local destroy = mount(App, game.StarterGui)
```

View file

@ -1,32 +1,40 @@
# Reactivity API: Core # Reactivity: Core
<br/> ## Scopes
Vide code can run in one of two scopes: <Badge type="info" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">STABLE</a></Badge> or <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>.
- Reactive scopes rerun if a source read within updates.
- Stable scopes never rerun.
- Reactive scopes cannot be created directly within another reactive scope.
- When a scope is destroyed, all scopes created within are also destroyed.
Different functions in Vide's API will run code in different scopes.
:::warning :::warning
Yielding is not allowed in any stable or reactive scope. Strict mode will check Yielding is not allowed in any stable or reactive scope. Strict mode will check
for this. for this.
::: :::
## root() ## root() <Badge type="info" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">STABLE</a></Badge>
Creates and runs a function in a new stable scope. Runs a function in a new stable scope.
- **Type** - **Type**
```luau ```luau
function root<T...>(fn: (() -> ()) -> T...): (() -> (), T...) function root<T...>(fn: (Destructor) -> T...): (Destructor, T...)
type Destructor = () -> ()
``` ```
- **Details** - **Details**
Returns a function to destroy the root scope. Also passes this function as Returns a destructor and any values returned by the callback.
the first argument into its callback.
All values returned by the callback are also returned following the destructor.
## source() ## source()
Creates a new source with the given value. Creates a new source.
- **Type** - **Type**
@ -40,71 +48,64 @@ Creates a new source with the given value.
- **Details** - **Details**
Calling the returned source with no argument will return its stored value, Call the returned source with no argument to read its value.
calling with an argument will set a new value. Call the returned source with an argument to set its value.
- **Example** - **Example**
```luau ```luau
local count = source(0) local count = source(0)
print(count())-- 0
count() -- 0 count(count() + 1)
print(count()) -- 1
count(count() + 1) -- 1
``` ```
## effect() ## effect() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Runs a side-effect in a new reactive scope on source update. Runs a function in a new reactive scope.
- **Type** - **Type**
```luau ```luau
function effect(callback: () -> ()) function effect(fn: () -> ())
``` ```
- **Details** - **Details**
Any time a source referenced in the callback is updated, the callback will The function is ran once immediately.
be reran.
The callback is ran once immediately.
- **Example** - **Example**
```luau ```luau
local num = source(1) local count = source(1)
effect(function() effect(function()
print(num()) print(count())
end) end)
-- prints 1 -- prints 1
num(num() + 1) count(2)
-- prints 2 -- prints 2
``` ```
## derive() ## derive() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Derives a new source in a new reactive scope from existing sources. Runs a function in a new reactive scope to compute a value for new source.
- **Type** - **Type**
```luau ```luau
function derive<T>(source: () -> T): () -> T function derive<T>(fn: () -> T): () -> T
``` ```
- **Details** - **Details**
The derived source will have its value recalculated when any source source Anytime the reactive scope reruns, the output source value is set to what is
it derives from is updated. returned.
Anytime its value is recalculated it is also cached, subsequent calls will The function is ran once immediately.
retun this cached value until it recalculates again.
The callback is ran once immediately.
- **Example** - **Example**
@ -112,11 +113,43 @@ Derives a new source in a new reactive scope from existing sources.
local count = source(0) local count = source(0)
local text = derive(function() return `count: {count()}` end) local text = derive(function() return `count: {count()}` end)
text() -- "count: 0" print(text()) -- "count: 0"
count(1) count(1)
text() -- "count: 1" print(text()) -- "count: 1"
``` ```
-------------------------------------------------------------------------------- A `derive()` should be used instead of a pure function when you expect it to
be read multiple times between updates, because `derive()` will cache the
result to prevent recomputing it on every read.
::: code-group
```luau [Pure Function]
local count = source(0)
local text = function()
print "ran"
return `count: {count()}`
end
count(1)
print(text()) -- prints "ran" followed by "count: 1"
print(text()) -- prints "ran" followed by "count: 1"
```
```luau [Derived Source]
local count = source(0)
local text = derive(function() -- [!code highlight]
print "ran"
return `count: {count()}`
end) -- [!code highlight]
count(1) -- prints "ran"
print(text()) -- prints "count: 1"
print(text()) -- prints "count: 1"
```
:::

View file

@ -0,0 +1,212 @@
# Reactivity: Dynamic Scoping
Dynamic scoping is the act of creating and destroying new scopes in response to
source updates. Vide provides functions for some common use-cases to do this.
## show() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Shows a component if the source is truthy. Optionally shows a fallback component
if the source is falsey.
- **Type**
```luau
function show<T>(source: () -> unknown, component: () -> T): () -> T?
function show<T, U>(source: () -> unknown, component: () -> T, fallback: () -> U): () -> T | U
```
- **Details**
Creates a reactive scope internally to detect source updates.
The component is run in a stable scope when truthy, otherwise the stable
scope is destroyed.
Returns a source holding an instance of the currently shown component or
`nil` if no component is currently shown.
## switch() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Shows one of a set of components depending on a source and a mapping table.
- **Type**
```luau
function switch<K, V>(source: () -> K): (map: Map<K, () -> V>) () -> V?
```
- **Details**
Creates a reactive scope internally to detect source updates.
When the source updates, its value is inputted into a map to get a component
constructor. This component is then run in a stable scope. The previous
stable scope is destroyed.
Returns a source holding an instance of the currently shown component or
`nil` if no component is currently shown.
- **Example**
```luau
local logged = source(false)
local button = switch(logged) {
[true] = function()
return Button { Text = "Log out", Toggle = logged }
end,
[false] = function()
return Button { Text = "Log in", Toggle = logged }
end
}
```
## indexes() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Shows a component for each index in a table.
- **Type**
```luau
function indexes<KI, VI, VO>(
source: () -> Map<KI, VI>,
transform: (value: () -> VI, index: KI) -> VO
): Array<VO>
- **Details**
Creates a reactive scope internally to detect source updates.
When the source table updates, a component is generated for each index in
the table.
- For any added index, the `transform` function is run in a new stable
scope to produce an instance that is cached.
- For any removed index, the stable scope for that index is destroyed.
The `transform` function is called with:
1. A *source containing the index's value*.
2. The *index itself*.
Anytime an existing index's value changes, the `transform` function is not
rerun, instead, that index's corresponding source is updated with the new
value.
Returns a source holding an array of instances currently shown.
- **Example**
```luau
type Item = {
name: string,
icon: number
}
local items = source {} :: () -> Array<Item>
local displays = indexes(items, function(item, i)
return ItemDisplay {
Name = function()
return i .. ": " .. item().name
end,
Image = function()
return "rbxassetid://" .. item().icon
end,
}
end)
```
## values() <Badge type="tip" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">REACTIVE</a></Badge>
Shows a component for each value in a table.
- **Type**
```luau
function values<KI, VI, VO>(
source: () -> Map<KI, VI>,
transform: (value: VI, index: () -> KI) -> VO
): Array<VO>
- **Details**
Operates with the same idea as `indexes()`, but applied to values instead of
indexes.
Creates a reactive scope internally to detect source updates.
When the source table updates, a component is generated for each value in
the table.
- For any added value, the `transform` function is run in a new stable scope
to produce an instance that is cached.
- For any removed value, the stable scope for that value is destroyed.
The `transform` function is called with:
1. The *value itself*.
2. A *source containing the value's index*.
Anytime an existing value's index changes, the `transform` function is not
rerun, instead, that value's corresponding source is updated with the new
index.
Returns a source holding an array of instances currently shown.
::: warning
Having the same values appear multiple times in the input source table can
cause unexpected behavior. Strict mode has checks for this.
:::
- **Example**
```luau
type Item = {
name: string,
icon: number
}
local items = source {} :: () -> Array<Item>
local displays = values(items, function(item, i)
return ItemDisplay {
Name = function()
return i() .. ": " .. item.Name
end
Image = "rbxassetid://" .. item.icon,
}
end)
```
- **Extra**
When should you use `indexes()` and `values()`?
`values()` should be used when you have a fixed set of objects where the
same objects can be re-arranged in the source table. It maps a value to a
UI element.
e.g.
- List of all players.
- Inventory of items.
- Chat message history.
- Toast notifications.
`indexes()` should be used in other cases, especially when your source table
has primitive values. It maps an index to a UI element.
e.g.
- List of character or weapon stats.
In most cases, both functions will produce the same observed result.
The main difference is performance, picking the right function to use can
result in less property updates and less re-renders. One case to note is
that `values()` works nicely when animating re-ordering of instances, since
the source index can be used to animate a change in position for the UI
element.
--------------------------------------------------------------------------------

View file

@ -1,218 +0,0 @@
# Reactivity API: Control Flow
<br/>
## show()
Shows one of two components depending on an input source.
- **Type**
```luau
function show<T>(source: () -> unknown, component: () -> T): () -> T?
function show<T, U>(source: () -> unknown, component: () -> T, fallback: () -> U): () -> T | U
```
- **Details**
Returns a source holding an instance of the currently shown component.
When the input source changes from a falsey to a truthy value, the
component will be reran under a new stable scope. If it changes from a
truthy to falsey value, the stable scope the component was created in will
be destroyed, and the returned source will output `nil`, or a fallback
component if given.
The fallback component is also ran under a new stable scope, and destroyed
when the input source switches back to truthy.
## switch()
Shows one of a set of components depending on an input source and a mapping table.
- **Type**
```luau
function switch<K, V>(source: () -> K): (map: Map<K, () -> V>) -> V?
```
- **Details**
Returns a source holding an instance of the currently shown component.
When the input source changes, the new value will be used to lookup a given
mapping table to get a component, which will be ran under a new stable
scope. If the input source changes, the stable scope the component was
created in will be destroyed, and a new component created under a new
stable scope. If no component is found for an input value, the switch will
output `nil`.
- **Example**
```luau
local logged = source(false)
local button = switch(logged) {
[true] = function()
return Button { Text = "Log out", Toggle = logged }
end,
[false] = function()
return Button { Text = "Log in", Toggle = logged }
end
}
```
## indexes()
Maps each index in a table source to an object.
- **Type**
```luau
function indexes<KI, VI, VO>(
source: () -> Map<KI, VI>,
transform: (value: () -> VI, index: KI) -> VO
): Array<VO>
- **Details**
Returns a source holding an array of instances currently shown.
When the input source changes, each *index* in the new table is compared with
the last input table.
- For any new index, the `transform` function is ran under a new stable
scope to produce a new instance.
- For any removed index, the stable scope for that index is destroyed.
- Unchanged indexes are untouched.
The transform function is called only ever *once* for each index in the
source table.
1. First argument is a *source containing the index's value*.
2. Second argument is the *index itself*.
Anytime an existing index's value changes, the transform function is not
rerun, instead the source value for that index will update, causing anything
depending on it to update too.
- **Example**
The intended purpose of this function is to map each index in a table to
a UI element.
```luau
type Item = {
name: string,
icon: number
}
local items = source {} :: () -> Array<Item>
local displays = indexes(items, function(item, i)
return ItemDisplay {
Name = function()
return i .. ": " .. item().name
end,
Image = function()
return "rbxassetid://" .. item().icon
end,
}
end)
```
## values()
Maps each value in a table source to an object.
- **Type**
```luau
function values<KI, VI, VO>(
source: () -> Map<KI, VI>,
transform: (value: VI, index: () -> KI) -> VO
): Array<VO>
- **Details**
Returns a source holding an array of instances currently shown.
When the input source changes, each *value* in the new table is compared with
the last input table. Similar to `indexes()` but for values instead of indexes.
- For any new value, the `transform` function is ran under a new stable
scope to produce a new instance.
- For any removed value, the stable scope for that value is destroyed.
- Unchanged values are untouched.
The transform function is only ever called *once* for each value in the
source table.
1. First argument is the *value itself*.
2. Second argument is a *source containing the value's index*.
Anytime an existing value's index changes, the transform function is not
rerun, instead the source index for that value will update, causing anything
depending on it to update too.
::: warning
Having primitive values in the input source table can cause unexpected
behavior, as duplicate values can result in multiple tranforms being ran for
a single value, meaning there can be multiple source indexes bound to the
same UI element. Strict mode has checks for this.
:::
- **Example**
The intended purpose of this function is to map each value in a table to
a UI element.
```luau
type Item = {
name: string,
icon: number
}
local items = source {} :: () -> Array<Item>
local displays = values(items, function(item, i)
return ItemDisplay {
Name = function()
return i() .. ": " .. item.Name
end
Image = "rbxassetid://" .. item.icon,
}
end)
```
- **Extra**
When should you use `indexes()` and `values()`?
`values()` should be used when you have a fixed set of objects where the
same objects can be re-arranged in the source table. It maps a value to a
UI element.
e.g.
- List of all players.
- Inventory of items.
- Chat message history.
- Toast notifications.
`indexes()` should be used in other cases, especially when your source table
has primitive values. It maps an index to a UI element.
e.g.
- List of character or weapon stats.
In most cases, both functions will appear to have the same behavior.
The main difference is performance, picking the right function to use can
result in less property updates and less re-renders. One case to note is
that `values()` works nicely when animating re-ordering of instances, since
the value is not destroyed when indexes are changed, and the source index
can be used to animate a change in position for the UI element.
--------------------------------------------------------------------------------

View file

@ -1,16 +1,15 @@
# Reactivity API: Utility # Reactivity: Utility
## cleanup() ## cleanup()
Runs a callback anytime a scope is reran or destroyed. Queues a callback to run when a scope is reran or destroyed.
- **Type** - **Type**
```luau ```luau
function cleanup(callback: () -> ()) function cleanup(v: Function | Disconnectable | Destroyable)
function cleanup(obj: Destroyable)
function cleanup(obj: Disconnectable)
type Function = () -> ()
type Destroyable = { destroy: () -> () } type Destroyable = { destroy: () -> () }
type Disconnectable = { disconnect: () -> () } type Disconnectable = { disconnect: () -> () }
``` ```
@ -18,20 +17,27 @@ Runs a callback anytime a scope is reran or destroyed.
- **Example** - **Example**
```luau ```luau
local data = source(1) local count = source(0)
effect(function() local destroy = root(function()
local label = create "TextLabel" { Text = data() } effect(function()
count()
cleanup(function() cleanup(function()
label:Destroy() print "cleaned"
end)
end) end)
end) end
-- nothing printed yet
count(1) -- prints "cleaned"
count(2) -- prints "cleaned"
destroy() -- prints "cleaned"
``` ```
## untrack() ## untrack() <Badge type="info" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">STABLE</a></Badge>
Runs a given function in a new stable scope. Runs a function in a new stable scope.
- **Type** - **Type**
@ -55,16 +61,15 @@ Runs a given function in a new stable scope.
end) end)
print(sum()) -- 0 print(sum()) -- 0
b(1) b(1) -- untracked so reactive scope created by derive() does not rerun
print(sum()) -- 0 print(sum()) -- 0
a(1) a(1) -- reactive scope created by derive() reruns
print(sum()) -- 2 print(sum()) -- 2
``` ```
## read() ## read()
Utility used to read a value that is either a primitive or a source. Sources Utility used to read a value that is either a primitive or a source.
read can still be tracked inside a reactive scope.
- **Type** - **Type**
@ -74,8 +79,8 @@ read can still be tracked inside a reactive scope.
## batch() ## batch()
Runs a given function where any source updates made within the function do not Runs a function where any source updates made within the function do not
trigger effects until after the function finishes running. trigger effects until after the function ends.
- **Type** - **Type**
@ -86,11 +91,29 @@ trigger effects until after the function finishes running.
- **Details** - **Details**
Improves performance when an effect depends on multiple sources, and those Improves performance when an effect depends on multiple sources, and those
sources need to be updated. Updating those sources inside a batch call will sources need to be updated.
only cause the effect to run once after the batch call ends instead of after
each time a source is updated.
## context() - **Example**
```luau
local a = source(0)
local b = source(0)
effect(function()
print(a() + b())
end)
-- prints "0"
batch(function()
a(1) -- no print
b(2) -- no print
end)
-- prints "3"
```
## context() <Badge type="info" text="STABLE"><a href="/vide/api/reactivity-core#Scopes">STABLE</a></Badge>
Creates a new context. Creates a new context.
@ -101,15 +124,17 @@ Creates a new context.
type Context<T> = type Context<T> =
() -> T -- get () -> T -- get
& (T, () -> ()) -> () -- set & <U>(T, () -> U) -> U -- set
``` ```
- **Details** - **Details**
Calling `context()` returns a new context function. Calling `context()` returns a new context function.
Call this function with no arguments to get the context value. Call this function with no arguments to get the context value.
Call this function with a value and a callback to set a new context with the Call this function with a value and a function to create a new context with
given value. the given value.
The new context is run under a stable scope.
- **Example** - **Example**
@ -131,4 +156,3 @@ Creates a new context.
end) end)
``` ```
--------------------------------------------------------------------------------

View file

@ -14,25 +14,23 @@ and identifying improper usage.
Currently, strict mode will: Currently, strict mode will:
1. Run derived sources twice a source updates. 1. Run reactive scopes twice when a source updates.
2. Run effects twice when a source updates. 2. Throw an error if yields occur where they are not allowed.
3. Throw an error if yields occur where they are not allowed. 3. Checks for `indexes()` and `values()` outputting primitive values.
4. Checks for `indexes()` and `values()` returning primitive values. 4. Checks for `values()` input having duplicate values.
5. Checks for `values()` input having duplicate values. 5. Checks for duplicate nested properties at same depth.
6. Checks for duplicate nested properties at same depth. 6. Better error reporting and stack traces + creation traces of property bindings.
7. Better error reporting and stack traces + creation traces of property bindings.
By rerunning derived sources and effects twice each time they update, it helps By rerunning reactive scopes twice each time they update, it helps ensure that
ensure that derived source computations are pure, and that any computations are pure, and that any cleanup is done correctly.
cleanups made in derived sources or effects are done correctly.
Accidental yielding within reactive scopes can break Vide's reactive graph, Accidental yielding within reactive scopes can break Vide's reactive graph,
which strict mode will catch. which strict mode will catch.
As well as additional safety checks, Vide will dedicate extra resources to As well as additional safety checks, Vide will dedicate extra resources to
recording and better emitting stack traces where errors occur, particularly recording and better emitting stack traces where errors occur, particularly
when binding properties to sources. when implicit effects are created for instance property updating.
It is recommended to develop UI with strict mode and to disable it when pushing to It is recommended to develop UI with strict mode and to disable it when pushing to
production. In Roblox, production code compiles at O2 by default, so you don't production. In Roblox, production code compiles at O2 by default, so you do not
need to worry about disabling strict mode unless you have manually enabled it. need to worry about disabling strict mode unless you have manually enabled it.

View file

@ -1,192 +0,0 @@
# Nested Scopes
Nesting scopes gives you finer control over the reactive graph, but needs more work to do. The built-in control flow functions try to cover the
most common cases, but they do not cover all of them.
This tutorial will demonstrate how to implement a `show()` control flow function
using just sources and effects.
```luau
local mount = vide.mount
local source = vide.source
local show = vide.show
local function Counter()
local count = source(0)
return create "TextButton" {
Text = count,
Activated = function() count(count() + 1) end
}
end
root(function()
local toggled = source(true)
show(toggled, Button)
end)
```
```mermaid
%%{init: {
"theme": "base",
"themeVariables": {
"primaryColor": "#1B1B1F",
"primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F",
"lineColor": "#79B8FF",
"tertiaryColor": "#161618",
"tertiaryBorderColor": "#1C1C1F"
}
}}%%
graph
subgraph mount
direction LR
toggle --> show
subgraph show[show effect]
text[Text effect]
end
end
```
Above is the reactive graph for `show()`. It creates a new effect depending on
`toggle` where anytime `toggle` is truthy, it will create a new `Counter`. The
`show` effect calls `Counter`, which creates a new reactive scope to update its
text whenever `count` changes. As per the rules of reactive scopes, a reactive
scope rerunning will destroy any scopes created within it. So the text
effect's reactive scope is destroyed whenever the show effect is rerun.
The same can be achieved without the use of `show()`:
```luau
local mount = vide.mount
local source = vide.source
local effect = vide.effect
local cleanup = vide.cleanup
local function Counter()
local count = source(0)
return create "TextButton" {
Text = count,
Activated = function() count(count() + 1) end
}
end
mount(function()
local toggled = source(true)
effect(function()
if toggled() then
local destroy = root(function()
Counter()
end)
cleanup(destroy)
end
end)
end)
```
```mermaid
%%{init: {
"theme": "base",
"themeVariables": {
"primaryColor": "#1B1B1F",
"primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F",
"lineColor": "#79B8FF",
"tertiaryColor": "#161618",
"tertiaryBorderColor": "#1C1C1F"
}
}}%%
graph
subgraph mount
direction LR
toggle --> effect
subgraph effect
subgraph mount2[inner mount]
text[Text effect]
end
end
end
```
This is another way to achieve the same. Here we use `root()` within the effect
to manually create and destroy a new stable scope whenever the effect reruns.
The reason for creating a stable scope is to prevent the effect from tracking
any sources that may be read inside the `Counter()` call. Otherwise, the effect
may be rerun needlessly and recreate the counter.
Alternatively, instead of using `root()`:
```luau
local mount = vide.mount
local source = vide.source
local effect = vide.effect
local untrack = vide.untrack
local function Counter()
local count = source(0)
return create "TextButton" {
Text = count,
Activated = function() count(count() + 1) end
}
end
mount(function()
local toggled = source(true)
effect(function()
if toggled() then
untrack(Button)
end
end)
end)
```
```mermaid
%%{init: {
"theme": "base",
"themeVariables": {
"primaryColor": "#1B1B1F",
"primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F",
"lineColor": "#79B8FF",
"tertiaryColor": "#161618",
"tertiaryBorderColor": "#1C1C1F"
}
}}%%
graph
subgraph mount
direction LR
toggle --> effect
subgraph effect
text[Text effect]
end
end
```
Without the use of `untrack()`, an error would occur, since Vide does not allow
the creation of reactive scopes inside reactive scopes. `untrack()` creates a
stable scope inside the reactive scope, and we can create another reactive scope
inside that stable scope. The
reason for this, is because if the `Counter` component reads from a source
internally, that can cause the reactive scope calling `Counter()` to track that
source, causing unintentional reruns. As a guard against this, you are forced to
use `untrack()` to create nested reactive scopes.
The final result is the same as using the `show()` component. An effect is
created which creates the counter, which creates its own reactive scope. The
effect rerunning causes the counter's internal reactive scope to be destroyed,
making sure everything is cleaned up.

View file

@ -1 +0,0 @@
# show()

View file

@ -1 +0,0 @@
# switch()

View file

@ -1 +0,0 @@
# indexes()

View file

@ -1 +0,0 @@
# values()

View file

@ -6,10 +6,16 @@ Vide is heavily inspired by [Solid](https://www.solidjs.com/).
## Why Vide? ## Why Vide?
Vide provides a reactive and declarative API to simplify managing UI. Vide's reactive and declarative API aims to let you program UI as simply as
possible, with a strong focus on how data flows through your application.
Some of the main focuses behind Vide's design choices: Some of Vide's main design choices:
- Minimal syntax - Syntax minimal.
- Complete typechecking - Data oriented.
- Independence from instances - Typechecking compatible.
- Instance independent.
Vide's reactivity operates with the concept
of scopes which carries a learning curve, though is what makes Vide's minimal
syntax possible. The crash course will introduce these concepts gradually.

View file

@ -9,10 +9,10 @@ destroyed, or when a stable scope is destroyed.
local root = vide.root local root = vide.root
local source = vide.source local source = vide.source
local effect = vide.effect local effect = vide.effect
local cleanup = vide.cleanup
local count = source(0) local count = source(0)
local destroy = root(function() local destroy = root(function()
effect(function() effect(function()
local x = count() local x = count()

View file

@ -1,98 +0,0 @@
# Control Flow
Eventually you may need a way to dynamically create and destroy UI elements
resulting from source updates. Vide provides functions to help you do this,
known as *control flow* functions.
These functions return new sources, which hold the instances to be displayed.
The new sources can be used in `create()` to update the children of a container
instance.
## indexes()
`indexes()` *maps* each table index to a new UI element that can
update to display the current value at that index. Each table index is given a
single corresponding UI element.
```luau
local list = source {
"finish the crash course",
"star Vide's GitHub"
}
local function TodoList(props: { list: () -> Array<string> })
return create "Frame" {
create "UIListLayout" {},
indexes(list, function(todo, i)
return create "TextLabel" {
Text = function()
return i .. ": " .. todo()
end,
LayoutOrder = i
}
end)
}
end
TodoList { list = list }
```
For each index in the given source table, the given function to `indexes()` will
be run in a new stable scope with:
1. a source containing the value at the index
2. the index itself
When the value at an index is changed, the function is not reran. Instead, the
given source for that index is updated.
Any time the input source table is updated, the given function will be ran for
any newly added indexes, while any removed indexes (indexes now with a `nil`
value), will have its corresponding stable scope destroyed.
The reactive graph for the above example:
```mermaid
%%{init: {
"theme": "base",
"themeVariables": {
"primaryColor": "#1B1B1F",
"primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F",
"lineColor": "#79B8FF",
"tertiaryColor": "#161618",
"tertiaryBorderColor": "#1C1C1F"
}
}}%%
graph
subgraph root ["root scope"]
direction LR
todoList --> indexes -.- subroot1 & subroot2
subgraph subroot1 ["indexes scope 1"]
direction LR
value1[todo] --> prop1["prop binding"]
end
subgraph subroot2 ["indexes scope 2"]
direction LR
value2[todo] --> prop2[prop binding]
end
end
```
When you edit a table in a source, you must set that table again to actually
update the source.
```luau
local src = source { 1, 2 }
local data = src()
table.insert(data, 3) -- no effects will run
src(data) -- effects will run
```

View file

@ -0,0 +1,158 @@
# Dynamic Scoping
Eventually you may need a way to dynamically create and destroy UI elements
resulting from source updates. Vide provides functions to help you do this,
known as *dynamic scope* functions.
These functions create and destroy components for you in response to source
updates. They return a source containing the created component. This source can
be parented as a child which will update the shown children whenever the source
updates.
The simplest example is using `show()`.
```luau
local source = vide.source
local create = vide.create
local show = vide.show
local root = vide.root
function Button(props: { Text: string, Activated: () -> () })
return create "TextButton" {
Text = props.Text,
Activated = props.Activated
}
end
function Menu()
return create "TextLabel" {
Text = "This is a menu"
}
end
function App()
local toggled = source(false)
return create "ScreenGui" {
Button {
Text = "Toggle Menu",
Activated = function()
toggled(not toggled())
end
},
show(toggled, Menu) -- [!code highlight]
}
end
root(function()
App().Parent = game.StarterGui
end)
```
This is a complete example of rendering UI which has a single button that
toggles the opening of a menu.
--------------------------------------------------------------------------------
Another common function is `indexes()`. This function creates a component for
each index in a table.
Each component created is done so in a new and independent stable scope. The
indexes of the table are checked each source update to prevent redunant
destruction and recreation of UI elements.
```luau
local source = vide.source
local create = vide.create
local indexes = vide.indexes
local root = vide.root
local function Todo(props: {
Text: () -> string,
Position: number,
Activated: () -> ()
})
return create "TextButton" {
Text = function() return props.Position .. ": " .. props.Text() end,
LayoutOrder = props.Position,
Activated = Activated
}
end
local function TodoList(props: { List: () -> Array<string> })
return create "Frame" {
create "UIListLayout" {},
indexes(props.List, function(text, i) -- [!code highlight]
return Todo {
Text = text,
Position = i,
Activated = function() -- remove the todo when clicked
local list = props.List()
table.remove(list, i)
props.List(list)
end
}
end)
}
end
function App()
local list = source {
"finish the crash course",
"star Vide's GitHub"
}
return create "ScreenGui" {
TodoList { List = list },
}
end
root(function()
App().Parent = game.StarterGui
end)
```
The reactive graph for the above example:
```mermaid
%%{init: {
"theme": "base",
"themeVariables": {
"primaryColor": "#111720",
"primaryTextColor": "#fff",
"primaryBorderColor": "#111720",
"lineColor": "#79B8FF",
"tertiaryColor": "#0d131b",
"tertiaryBorderColor": "#0d131b"
}
}}%%
graph
subgraph root ["root"]
direction LR
todoList --> indexes -.- subroot1 & subroot2
subgraph subroot1 ["indexes scope 1"]
direction LR
value1[todo] --> prop1["prop binding"]
end
subgraph subroot2 ["indexes scope 2"]
direction LR
value2[todo] --> prop2[prop binding]
end
end
```
When you edit a table in a source, you must set that table again to actually
update the source.
```luau
local src = source { 1, 2 }
local data = src()
table.insert(data, 3) -- no effects will run
src(data) -- effects will run
```

View file

@ -1,13 +1,11 @@
# Actions # Actions
Actions in Vide are special callbacks that you can pass along with properties, Actions are special callbacks that you can pass along with properties,
to run some code on an instance receiving them. to run some code on an instance receiving them.
```luau ```luau
local action = vide.action local action = vide.action
```
```luau
create "TextLabel" { create "TextLabel" {
Text = "test", Text = "test",
@ -24,6 +22,7 @@ action used to listen for property changes:
```luau ```luau
local action = vide.action local action = vide.action
local source = vide.source
local effect = vide.effect local effect = vide.effect
local cleanup = vide.cleanup local cleanup = vide.cleanup
@ -49,7 +48,7 @@ effect(function()
print(output()) print(output())
end) end)
instance.Text = "foo" -- "foo" will be printed from the effect instance.Text = "foo" -- "foo" will be printed by the effect
``` ```
The source `output` will be updated with the new property value any time it is The source `output` will be updated with the new property value any time it is

View file

@ -23,6 +23,7 @@ local count = source(0)
local ran = 0 local ran = 0
effect(function() effect(function()
count()
ran += 1 ran += 1
end) end)

View file

@ -30,7 +30,7 @@ Created by:
- `root()` - `root()`
- `untrack()` - `untrack()`
- `switch()` - `show()`
- `indexes()` - `indexes()`
Stable scopes do not track sources and never rerun. Stable scopes do not track sources and never rerun.
@ -47,23 +47,14 @@ Created by:
Reactive scopes do track sources and will rerun when those sources update. Reactive scopes do track sources and will rerun when those sources update.
Reactive scopes cannot be created within a reactive scope, but stable scopes Reactive scopes cannot be created within a reactive scope, but stable scopes
can. can be created within a reactive scope.
## Scope Owners ## Scope Cleanup
A scope created within another scope is *owned* by the other scope, with the When a scope is rerun or destroyed, all scopes created within it are
exception of the scope created by `root()`. automatically destroyed.
When a scope is rerun or destroyed, all scopes owned by it are automatically Any functions queued by `cleanup()` are also ran.
destroyed.
`root()` creates a stable scope with no owner, instead it is destroyed manually.
## Cleanup
Arbitrary code to run whenever a stable or reactive scope is rerun or destroyed.
Queue a function to run using `cleanup()`.
## Reactive Graph ## Reactive Graph
@ -93,12 +84,12 @@ end)
%%{init: { %%{init: {
"theme": "base", "theme": "base",
"themeVariables": { "themeVariables": {
"primaryColor": "#1B1B1F", "primaryColor": "#111720",
"primaryTextColor": "#fff", "primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F", "primaryBorderColor": "#111720",
"lineColor": "#79B8FF", "lineColor": "#79B8FF",
"tertiaryColor": "#161618", "tertiaryColor": "#0d131b",
"tertiaryBorderColor": "#1C1C1F" "tertiaryBorderColor": "#202530"
} }
}}%% }}%%
@ -118,6 +109,5 @@ Notes:
- An update to `count` will cause `text` to rerun, which - An update to `count` will cause `text` to rerun, which
then causes `effect` to rerun. then causes `effect` to rerun.
- When the root scope is destroyed, `text` and - When the root scope is destroyed, `text` and
`effect` will be destroyed alongside it, since they are `effect` will be destroyed alongside it, since they were created within it.
owned by it. `count` will be untouched and future updates `count` will be untouched and future updates to `count` will have no effect.
to `count` will have no effect.

View file

@ -1,6 +1,6 @@
# Effects # Effects
Effects are functions that are ran in response to source updates. They are Effects are functions that are ran in response to source updates.
A source and effect is analogous to a signal and connection. A source and effect is analogous to a signal and connection.
Effects are created using `effect()`. Effects are created using `effect()`.
@ -23,7 +23,10 @@ count(1)
Any source read inside an effect is tracked and will rerun the effect when Any source read inside an effect is tracked and will rerun the effect when
that source is updated. that source is updated.
Derived sources are also tracked, it doesn't matter how deeply nested The effect runs its callback once immediately to initially figure out what
sources are being read.
Derived sources are also tracked, it does not matter how deeply nested
inside a function a source is. inside a function a source is.
```luau ```luau
@ -47,3 +50,22 @@ count(2)
If a source is updated with the same value it already had, it will not rerun If a source is updated with the same value it already had, it will not rerun
effects depending on it. effects depending on it.
You can also read from a source within an effect without the effect tracking it.
```lua
local source = vide.source
local effect = vide.effect
local untrack = vide.untrack
local a = source(0)
local b = source(0)
effect(function()
print(`a: {a()} b: {untrack(b)}`)
end)
a(1) -- prints "a: 1 b: 0"
b(1) -- prints nothing
a(2) -- prints "a: 2 b: 1"
```

View file

@ -7,29 +7,31 @@ But the disconnecting of many signals and connections is tedious and verbose.
Vide instead operates on the concept of scopes which provides a much cleaner Vide instead operates on the concept of scopes which provides a much cleaner
API, given that you follow a few rules. API, given that you follow a few rules.
Scopes come in two flavors; stable and reactive. Thre are two types of scopes: stable and reactive.
- All scopes must be created within another scope with the exception of `root()` - A scope must be created within another scope.
- Stable scopes never rerun - Stable scopes never rerun.
- Reactive scopes can rerun - Reactive scopes can rerun.
- A reactive scope cannot be created within another reactive scope - A reactive scope cannot be created within another reactive scope, only within
a stable scope.
An exception to the first rule is `root()`, which creates the initial scope that
you destroy manually with a destructor function it returns.
`effect()` creates a reactive scope.
`root()` creates a stable scope. `root()` creates a stable scope.
`effect()` creates a reactive scope.
Whenever a scope is destroyed, any scope created within that scope is also Whenever a scope is destroyed, any scope created within that scope is also
destroyed, and so on. This is why all scopes must be created within another destroyed, and so on.
scope, except `root()` which is used to create the initial scope that you can
manually destroy.
```luau ```luau
local root = vide.root local root = vide.root
local source = vide.source local source = vide.source
local effect = vide.effect local effect = vide.effect
local function setup() local count = source(0)
local count = source(0)
local function setup()
effect(function() effect(function()
print(count()) print(count())
end) end)
@ -37,32 +39,16 @@ local function setup()
return count return count
end end
setup() -- will error since effect() tries to create a reactive scope outside of a stable scope setup() -- error, effect() tried to create a reactive scope with no stable scope
local count = root(setup) -- ok since effect() was called within a stable scope local destroy = root(setup) -- ok since effect() was called in a stable scope
count(1) -- prints "1"
```
The scope created by `root()` can be destroyed.
```luau
local function setup()
local count = source(0)
effect(function()
print(count())
end)
return count
end
local destroy, count = root(setup)
count(1) -- prints "1" count(1) -- prints "1"
count(2) -- prints "2"
destroy() destroy()
count(2) -- effect is destroyed; no longer prints count(3) -- reactive scope created by effect() is destroyed, it does not rerun
``` ```
Vide's reactivity can be represented graphically, as a *reactive graph*. Vide's reactivity can be represented graphically, as a *reactive graph*.
@ -73,12 +59,12 @@ The reactive graph for the above example looks like so:
%%{init: { %%{init: {
"theme": "base", "theme": "base",
"themeVariables": { "themeVariables": {
"primaryColor": "#1B1B1F", "primaryColor": "#111720",
"primaryTextColor": "#fff", "primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F", "primaryBorderColor": "#111720",
"lineColor": "#79B8FF", "lineColor": "#79B8FF",
"tertiaryColor": "#161618", "tertiaryColor": "#0d131b",
"tertiaryBorderColor": "#161618" "tertiaryBorderColor": "#0d131b"
} }
}}%% }}%%
@ -90,7 +76,7 @@ subgraph root
end end
``` ```
When the stable `root()` is destroyed, the reactive `effect()` When the stable `root()` scope is destroyed, the reactive `effect()`
scope will also be destroyed since it was created within it. scope will also be destroyed since it was created within it.
This is important because you may have an effect that updates the property of a This is important because you may have an effect that updates the property of a

View file

@ -1,10 +1,8 @@
# Stateful Components # Reactive Components
Stateful components in Vide are created using sources and effects - sources to Reactive components in Vide are created using sources and effects - sources to
store the data, and effects to display the data. store the data, and effects to display the data.
## Internal State
```luau ```luau
local create = vide.create local create = vide.create
local source = vide.source local source = vide.source
@ -33,8 +31,6 @@ its internal count, and automatically update its text to reflect that count.
Each instance of `Counter()` will maintain its own independent count, since the Each instance of `Counter()` will maintain its own independent count, since the
count source is created inside the component. count source is created inside the component.
## External State
External sources can also be passed into components for them to use. External sources can also be passed into components for them to use.
```luau ```luau

View file

@ -3,7 +3,9 @@
Explicitly creating effects to update properties is tedious. You can Explicitly creating effects to update properties is tedious. You can
*implicitly* create an effect to update properties instead. *implicitly* create an effect to update properties instead.
```luau ::: code-group
```luau [Implicit Effect]
local create = vide.create local create = vide.create
local source = vide.source local source = vide.source
@ -22,6 +24,30 @@ local function Counter()
end end
``` ```
```luau [Explicit Effect]
local create = vide.create
local source = vide.source
local effect = vide.effect
local function Counter()
local count = source(0)
local instance = create "TextButton" {
Activated = function()
count(count() + 1)
end
}
effect(function()
instance.Text = "count: " .. count()
end)
return instance
end
```
:::
This example is equivalent to the example seen on the previous page. This example is equivalent to the example seen on the previous page.
Instead of explicitly creating an effect, assigning a (non-event) property a Instead of explicitly creating an effect, assigning a (non-event) property a
@ -46,12 +72,12 @@ local function List(props: { children: () -> { Instance } })
} }
end end
local list = List { children = items } -- creates a list with a single text label "A" local list = List { children = items } -- creates a list with text label "A"
items { items {
create "TextLabel" { Text = "B" }, create "TextLabel" { Text = "B" },
create "TextLabel" { Text = "C" } create "TextLabel" { Text = "C" }
} }
-- this will automatically unparent the text label "A", and parent the labels "B" and "C" -- this will automatically unparent text label "A", and parent labels "B" and "C"
``` ```

View file

@ -57,7 +57,8 @@ effect(function() text() end)
count(1) -- prints "ran" x1 count(1) -- prints "ran" x1
``` ```
`derive()` must also be called within a stable scope, just like `effect()`. Because `derive()` creates a reactive scope, it must be called within a stable
scope, just like `effect()`.
If the recalculated value is the same as the old value, the derived source will If the recalculated value is the same as the old value, the derived source will
not rerun the effects using it. not rerun the effects using it.
@ -68,12 +69,12 @@ The reactive graph for the above example:
%%{init: { %%{init: {
"theme": "base", "theme": "base",
"themeVariables": { "themeVariables": {
"primaryColor": "#1B1B1F", "primaryColor": "#111720",
"primaryTextColor": "#fff", "primaryTextColor": "#fff",
"primaryBorderColor": "#1B1B1F", "primaryBorderColor": "#111720",
"lineColor": "#79B8FF", "lineColor": "#79B8FF",
"tertiaryColor": "#161618", "tertiaryColor": "#0d131b",
"tertiaryBorderColor": "#161618" "tertiaryBorderColor": "#0d131b"
} }
}}%% }}%%
@ -86,7 +87,7 @@ end
``` ```
Deriving a source in this manner is similar to creating an effect to update Deriving a source in this manner is similar to creating an effect to update
another source. You should never manually do this using an effect however. another source. You should avoid doing this using an effect however.
Improper usage could accidently create infinite loops in the reactive graph. Improper usage could accidently create infinite loops in the reactive graph.
Always favour deriving when you need one source to update based on another Always favour deriving when you need one source to update based on another
source. source.

View file

@ -0,0 +1,144 @@
# Dynamic Scoping
Dynamic scoping is the act of creating and destroying new scopes in response to
source updates. This is needed for conditionally rendering parts of your UI,
such as opening and closing menus.
While Vide provides functions for common ways to do this, this section will
show how you can implement them yourself so you are not limited by only what is
provided.
## Recreating [`show()`](/api/reactivity-dynamic#show-reactive)
The most basic one, `show()`, can be
implemented yourself like so:
```luau
local function show(toggle: () -> unknown, component: () -> Instance)
return derive(function()
return if toggle() then untrack(component) else nil
end)
end
```
The main thing to note here is the use of `untrack()`. This function runs its
callback in a new stable scope. Without this, if the component were to create
a reactive scope, an error would occur since a reactive scope cannot be created
within a reactive scope.
```mermaid
%%{init: {
"theme": "base",
"themeVariables": {
"primaryColor": "#111720",
"primaryTextColor": "#fff",
"primaryBorderColor": "#444455",
"lineColor": "#79B8FF",
"tertiaryColor": "#0d131b",
"tertiaryBorderColor": "#444455"
}
}}%%
graph
subgraph derive ["derive (reactive)"]
subgraph untrack ["untrack (stable)"]
subgraph effect ["effect (reactive)"]
end
end
end
```
You can see from the above graph how the effect would not be created directly
inside the derive, there is a stable scope between them. This requirement exists
as a guard against unintentional rerendering of UI.
## Recreating [`switch()`](/api/reactivity-dynamic#switch-reactive)
```lua
local function switch(key)
return function(map)
return derive(function()
local component = map[key()]
return if component then untrack(component) else nil
end)
end
end
```
## Recreating [`indexes()`](/api/reactivity-dynamic#indexes-reactive)
This is a more complicated function because it manages multiple scopes at the
same time, unlike the previous functions. Because some scopes may persist
between reruns, we cannot use `untrack()` anymore which automatically destroys
on rerun; we must use `root()` where the lifetime of each scope is managed
manually and independently.
```lua
local function indexes<I, VI, VO>(
input: () -> Map<I, VI>,
transform: (value: () -> VI, index: I) -> VO
)
local index_caches = {} :: Map<I, {
previous_input: VI,
output: VO,
source: (VI) -> VI,
destroy: () -> ()
}?>
return derive(function()
local new_input = input()
-- destroy scopes of removed indexes
for i, cache in index_caches do
if new_input[i] == nil then
assert(cache).destroy()
index_caches[i] = nil
end
end
-- create scopes or update sources of added or changed index values
for i, v in new_input do
local cache = index_caches[i]
if cache == nil then -- no scope created for this index, create one
local src = source(v)
local destroy, result = root(function()
return transform(src, i)
end)
index_caches[i] = {
destroy = destroy,
source = src,
output = result,
previous_input = v
}
elseif cache.previous_input ~= v then -- scope exists, update source
cache.previous_input = v
cache.source(v)
else -- scope exists and value has not changed; do nothing
end
end
-- return the cached output values as an array
local array = table.create(#index_caches)
for _, cache in index_caches do
table.insert(array, assert(cache).output)
end
return array
end)
end
```
--------------------------------------------------------------------------------
Though the above functions are already provided to you by Vide, this serves as
an example for how you may create your own dynamic scope functions.