Simple timer for litecanvas

README.md

Simple Timer

Litecanvas plugin to handle simple timers.

Usage

litecanvas()

function init() {
  // load the plugin
  use(pluginSimpleTimer)

  // example: alert every 2 seconds
  every(2, () => {
    alert('hello')
  })
  
  // example: alert just once after 5 seconds
  // note: return "false" to cancel a timer
  // note: "executed" stores the number of times the callback has been called
  every(5, (executed) => {
    if (executed > 0) return false
    alert('once')
  })
  
  // note: every(0, fn) runs every frame
  let frames = 0
  every(0, () => {
    frames += 1
  })
}

Live Demo

code.js

/**
 * Simple Timer for Litecanvas 
 * @version 1.0.0
 */
function pluginSimpleTimer(engine) {
  const ev = 'before:update'

  function every(seconds, callback) {
    // time accumulator
    let acc = 0
    // how many times the callback has been called
    let i = 0
  
    const handler = (dt) => {
      acc += dt
      if (acc >= seconds) {
        acc -= seconds
        // returns "false" in your callback to cancel the timer
        if (false === callback(i++)) {
          cancel()
        }
      }
    }
    const cancel = () => engine.unlisten(ev, handler)

    engine.listen(ev, handler)

    // also, every() returns a function to cancel the timer manually 
    return cancel
  }

  return { every }
}

For more advance timers use the Timers plugin.