Maps
ECMAScript 6 introduces maps. A map is a simple key-value map and can iterate its elements in the order of their insertion. The following snippet shows some methods of the Map
type and their usage:
var founders = new Map(); founders.set("facebook", "mark"); founders.set("google", "larry"); founders.size; // 2 founders.get("twitter"); // undefined founders.has("yahoo"); // false for (var [key, value] of founders) { console.log(key + " founded by " + value); } // "facebook founded by mark" // "google founded by larry"
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