mirror of
https://github.com/centau/vide.git
synced 2026-08-20 14:41:37 +00:00
46 lines
1.3 KiB
Markdown
46 lines
1.3 KiB
Markdown
# Sources
|
|
|
|
*Sources* in Vide are special objects that store a single value. They are the
|
|
core of reactivity in Vide. Each source represents a source of data, and they
|
|
can be composed and derived to create new sources of data.
|
|
|
|
A source in Vide can be created using `source()`.
|
|
|
|
```lua
|
|
local source = vide.source
|
|
|
|
local count = source(0)
|
|
```
|
|
|
|
The value passed to `source()` is the initial value of the source.
|
|
|
|
The value of a source can be set by calling it with an argument, and can be read
|
|
by calling it with no arguments.
|
|
|
|
```lua
|
|
count(count() + 1) -- increment count by 1
|
|
```
|
|
|
|
Sources can be *derived* by wrapping them in functions. A wrapped source
|
|
effectively becomes a new source.
|
|
|
|
Derived sources should be pure functions. This is where the same output is
|
|
always produced for the same input no matter how many times it is reran.
|
|
|
|
```lua
|
|
local count = source(0)
|
|
|
|
local text = function()
|
|
return "count: " .. tostring(count())
|
|
end
|
|
|
|
print(text()) -- "count: 0"
|
|
count(1)
|
|
print(text()) -- "count: 1"
|
|
```
|
|
|
|
Sources on their own aren't very special, the above can be achieved with plain
|
|
variables. The real use for sources become apparent when used in combination
|
|
with Vide's *reactive scopes*. When a source is read from within a reactive
|
|
scope, it can automatically rerun the scope that reads it when the source is
|
|
updated in the future.
|