ES6 keys() iterator

by Rich Costello

JavaScript

let colors = [ "red", "green", "blue" ];
let tracking = new Set([1234, 5678, 9012]);
let data = new Map();
data.set("title", "Understanding ECMAScript 6");
data.set("format", "ebook");
for (let key of colors.keys()) {
    console.log(key);
}
for (let key of tracking.keys()) {
    console.log(key);
}
for (let key of data.keys()) {
    console.log(key);
}