A generator is iterable. It can be looped over with a for...of statement, and used in other constructs which depend on the iteration protocol.
function* range(n) {
for (let i = 0; i < n; ++i) {
yield i;
}
}
// looping
for (let n of range(10)) {
// n takes on the values 0, 1, ... 9
}
// spread operator
let nums = [...range(3)]; // [0, 1, 2]
let max = Math.max(...range(100)); // 99
Here is another example of use generator to custom iterable object in ES6. Here anonymous generator function function * used.
let user = {
name: "sam", totalReplies: 17, isBlocked: false
};
user[Symbol.iterator] = function *(){
let properties = Object.keys(this);
let count = 0;
let isDone = false;
for(let p of properties){
yield this[p];
}
};
for(let p of user){
console.log( p );
}