choo-shortcache/example/node_modules/nanoscheduler/index.js

choo nanocomponent cache shortcut

var assert = require('assert')

var hasWindow = typeof window !== 'undefined'

function createScheduler () {
  var scheduler
  if (hasWindow) {
    if (!window._nanoScheduler) window._nanoScheduler = new NanoScheduler(true)
    scheduler = window._nanoScheduler
  } else {
    scheduler = new NanoScheduler()
  }
  return scheduler
}

function NanoScheduler (hasWindow) {
  this.hasWindow = hasWindow
  this.hasIdle = this.hasWindow && window.requestIdleCallback
  this.method = this.hasIdle ? window.requestIdleCallback.bind(window) : this.setTimeout
  this.scheduled = false
  this.queue = []
}

NanoScheduler.prototype.push = function (cb) {
  assert.equal(typeof cb, 'function', 'nanoscheduler.push: cb should be type function')

  this.queue.push(cb)
  this.schedule()
}

NanoScheduler.prototype.schedule = function () {
  if (this.scheduled) return

  this.scheduled = true
  var self = this
  this.method(function (idleDeadline) {
    var cb
    while (self.queue.length && idleDeadline.timeRemaining() > 0) {
      cb = self.queue.shift()
      cb(idleDeadline)
    }
    self.scheduled = false
    if (self.queue.length) self.schedule()
  })
}

NanoScheduler.prototype.setTimeout = function (cb) {
  setTimeout(cb, 0, {
    timeRemaining: function () {
      return 1
    }
  })
}

module.exports = createScheduler