useInterval

useInterval lets you run a callback function repeatedly at a specified time interval (in milliseconds). It automatically handles timer creation, cleanup, and updates when the delay changes.

ui.hooks.useInterval(callback, delay_ms)

Reference

useInterval(callback, delay_ms)

Call useInterval at the top level of a component to execute a function repeatedly at a fixed time interval. When the component unmounts or the delay changes, the interval is automatically cleaned up.

ui.hooks.useInterval(function()
  print("Tick!")
end, 1000)

Parameters

Name	Type	Description
callback	function	The function to execute at each interval. It will be called repeatedly on every tick.
delay_ms	number | nil	The interval delay in milliseconds. If nil or <= 0, the interval is not started. Changing this value will restart the timer with the new delay.

Returns

useInterval does not return a value.

Its purpose is to schedule a repeating callback that automatically cleans up when the component unmounts or when delay_ms changes.

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Usage

Example: Simple Interval Counter

Use useInterval to update state every few milliseconds.

local ui = require("ascii-ui")
local useState = ui.hooks.useState
local useInterval = ui.hooks.useInterval
local Paragraph = ui.components.Paragraph

local Ticker = ui.createComponent("Ticker", function()
  local count, setCount = useState(0)

  useInterval(function()
    setCount(function(prev) return prev + 1 end)
  end, 1000) -- every 1 second

  return {
    Paragraph({ content = "Seconds elapsed: " .. count }),
  }
end)

return Ticker