Promise.all 是在什么规范中引入的？

Question

I'm trying to document the solution of a common interview question and how the solution has changed with language updates.

For example, const & let were introduced in ES2015 making the problem easier to solve.

At what specification year was Promise.all introduced?

Related Code

// solution using promises
//
function asyncMap(tasks, callback){
  tasks = tasks.map(task => new Promise(task))
  return Promise.all(tasks)
    .then(callback);
}


// solution using let and const introduced in ES2015
// released in 2015 and sometimes referred to as ES6
function asyncMap1(tasks, callback) {
  const results = [];
  let count = 0;
  for (let i = 0; i < tasks.length; i++) {
    tasks[i](function (val) {
      results[i] = val;
      count++;
      if (count === tasks.length) {
        callback(results);
      }
    });
  }
};


// before let was available an IIFE would be needed
//
function asyncMap2(tasks, callback) {
  var results = [];
  var count = 0;
  for (var i = 0; i < tasks.length; i++) {
    (function (i) {
      tasks[i](function (val) {
        results[i] = val;
        count++;
        if (count === tasks.length) {
          callback(results);
        }
      });
    })(i);
  }
};

Answer 1

By looking at the specification document it was at ES2015. More specific at June 2015.

ECMAScript® 2015 Language Specification

25.4.4.1 Promise.all ( iterable )

If you also want to know if you can use it, just ask it at Can I Use or follow this link .