src/utils/queue.js

/**
 * @file Queue
 * @author Alexander Rose <alexander.rose@weirdbyte.de>
 * @private
 */

function Queue (fn, argList) {
  var queue = []
  var pending = false

  if (argList) {
    for (var i = 0, il = argList.length; i < il; ++i) {
      queue.push(argList[ i ])
    }
    next()
  }

  function run (arg) {
    fn(arg, next)
  }

  function next () {
    var arg = queue.shift()
    if (arg !== undefined) {
      pending = true
      setTimeout(function () { run(arg) })
    } else {
      pending = false
    }
  }

    // API

  this.push = function (arg) {
    queue.push(arg)
    if (!pending) next()
  }

  this.kill = function () {
    queue.length = 0
  }

  this.length = function () {
    return queue.length
  }
}

export default Queue