defer.ts

let deferreds       = {} as { [key : string] : any[] }
let deferred_timers = {} as { [key : string] : number }

/*
 * If you're waiting wor a `window.something`, and are not sure when it
 * will appear (for example, you defer async load it), you can do the following:
 *
 *       defer('something', (something) => ...)
 *
 *  You can also check nested props:
 *
 *       defer('google.maps', (GoogleMaps) => ...)
 *
 *
 *  defer will poll window['something'], and when it appears, it will
 *  invoke the function with window['something']
 *
 *  Note: it will poll the window object for 90 seconds, and then will stop
 *
 */

export default function defer(what : string, action : Function) : void {
  const executeAndLog = (whatObj, actionFunc) => {
    if(what === 'mixpanel') {
      // console.log(what, actionFunc.toString())
    }
    actionFunc(whatObj)
  }

  const obj = checkNested(window, what.split('.'))

  if(obj !== void 0) {
    const actions = deferreds[what] || []

    actions.forEach((action) => executeAndLog(obj, action))
    executeAndLog(obj, action)
  } else {
    if(deferreds[what] === void 0) {
      deferreds[what] = []
    }

    deferreds[what].push(action)
    if(deferred_timers[what] === void 0) {
      let counter           = 0
      deferred_timers[what] = setInterval(() => {
        const obj = checkNested(window, what.split('.'))
        if(obj !== void 0) {
          clearInterval(deferred_timers[what])
          const actions = deferreds[what] || []
          actions.forEach((action) => executeAndLog(obj, action))
        } else {
          counter = counter + 1
          if(counter > 300) {
            clearInterval(deferred_timers[what])
          }
        }
      }, 300)
    }
  }
}

function checkNested(obj, what) {
  for(let i = 0; i < what.length; i++) {
    if(!obj || !obj.hasOwnProperty(what[i])) {
      return void 0
    }
    obj = obj[what[i]]
  }
  return obj
}