Promise static function implement

1. implement promisify

function promisify(fn) {
    return function(...args) {  
      return new Promise((resolve, reject) => {
         fn(...args, function(err, data) {
            if (err) return reject
         })  
      })
    }
}

2. implement Promise.all

Promise.all = function(values) {
  let ret = []
  let len = values.length
  return new Promise((resolve, reject) => {
    values.forEach((val, idx) => {
      Promise.resolve(val).then((data) => {
        ret[idx] = data
        if (--len === 0) {
          resolve(ret)  
        }
      }, reject)
    })
  })
}

3 implement Promise.race

Promise.race = function(values) {
  return new Promise((resolve, reject) => {
    values.forEach((val, idx) => {
        Promise.resolve(val).then(resolve, reject)
    })
  })
}

4 implement abort

function withAbort(userPromise) {
   let abort
   let p = new Promise((resolve, reject) => {
      abort = reject
   })
   abort = Promise.race([userPromise, p])
   p.abort = abort
   return p
}