RegExp.prototype.matches.js

RegExp.prototype.matches = function* (str) {
  let moreThanOnce = this.global || this.sticky;
  let myLastIndex = 0;
  
  do {
    // preserve lastIndex of another .exec() calls on same regexp
    let savedLastIndex = this.lastIndex;
    // use own state for lastIndex to match our str
    this.lastIndex = myLastIndex;
    let match = this.exec(str);
    // save new state & restore lastIndex for other .exec() calls
    myLastIndex = this.lastIndex;
    this.lastIndex = savedLastIndex;
    if (!match) break;
    yield match;
  } while (moreThanOnce);
};

var r = /[a-z]/g;

// 1) Just iterating

for (let match of r.matches('abc')) {
  console.log(match);
}

/*
["a"]
["b"]
["c"]
*/

// 2) Concurrent iterators - not easy with regular re.exec()

var iter1 = r.matches('abc');
var iter2 = r.matches('def');

for (let i = 0; i < 3; i++) {
  console.log('iter1:', iter1.next().value);
  console.log('iter2:', iter2.next().value);
}

/*
iter1: ["a"]
iter2: ["d"]
iter1: ["b"]
iter2: ["e"]
iter1: ["c"]
iter2: ["f"]
*/

// 3) All matched groups - requires manual collection with .exec

var matches = Array.from(/(\w+)=(\d+)/g.matches('x=1,y=2'));

/*
[
  [ 'x=1', 'x', '1' ],
  [ 'y=2', 'y', '2' ]
]
*/