let s = new Set() s.add("a") s.add("a") s.add("b") console.log("has b:" + s.has("b")) console.log(s.values()) console.log(s.entries()) // has b:true // [Set Iterator] { 'a', 'b' } // [Set Entries] { [ 'a', 'a' ], [ 'b', 'b' ] }

let map = new Map() map.set("a", 1) map.set("b", 2) console.log("siez:" + map.size) console.log("getValue a:" + map.get("a")) map.forEach((value, key) => { console.log(key + "/" + value) }) // siez:2 // getValue a:1 // a/1 // b/2

let hash = { keyA: "value-a", keyB: "value-b", } //---------- Object.keys Object.keys(hash).map((key) => console.log(key + "/" + hash[key])) //---------- Object.entries for (const [key, value] of Object.entries(hash)) { console.log(`${key}…