nanoraf/index.js

Only call RAF when needed

'use strict'

var assert = require('assert')

module.exports = nanoraf

// Only call RAF when needed
// (fn, fn?) -> fn
function nanoraf (render, raf) {
  assert.equal(typeof render, 'function', 'nanoraf: render should be a function')
  assert.ok(typeof raf === 'function' || typeof raf === 'undefined', 'nanoraf: raf should be a function or undefined')

  if (!raf) raf = window.requestAnimationFrame
  var redrawScheduled = false
  var args = null

  return function frame () {
    if (args === null && !redrawScheduled) {
      redrawScheduled = true

      raf(function redraw () {
        redrawScheduled = false

        var length = args.length
        var _args = new Array(length)
        for (var i = 0; i < length; i++) _args[i] = args[i]

        render.apply(render, _args)
        args = null
      })
    }

    args = arguments
  }
}