vide/docs/api/reactivity-utility.md
2023-09-21 19:14:55 +01:00

1.2 KiB

Reactivity API: Utility

cleanup()

Runs a callback anytime a reactive scope is reran or destroyed.

  • Type

    function cleanup(callback: () -> ())
    
  • Example

    local data = source(1)
    
    effect(function()
        local label = create "TextLabel" { Text = data() }
    
        cleanup(function()
            label:Destroy()
        end)
    end)
    

untrack()

Runs a given function where any sources read will not be tracked by a reactive scope.

  • Type

    function untrack<T>(source: () -> T): T
    
  • Details

    Updates made to a source passed to untrack() will not cause updates to anything depending on that source.

  • Example

    local a = source(0)
    local b = source(0)
    
    local sum = derive(function()
        return a() + untrack(b)
    end)
    
    print(sum()) -- 0
    b(1)
    print(sum()) -- 0
    a(1)
    print(sum()) -- 2
    

read()

Utility used to read a value that is either a primitive or a source. Sources read can still be tracked inside a reactive scope.

  • Type

    function read<T>(value: T | () -> T): T