JavaScript Array.fromメソッドを使ってMap からの配列の生成サンプル
環境
Windows 10 home 64bit
Google Chrome 107.0.5304.122
書式
const Mapの変数名 = new Map([[値1, 値2], …]);
Array.from(Mapの変数名)
Array.fromメソッドを使ってMapからの配列を生成します。
使用例
const mapA = new Map([[21, 34], [22, 55], [23, 66]]);
console.log(Array.from(mapA));
const mapB = new Map([['101', 'tokyo'], ['202', 'oosaka']]);
console.log(Array.from(mapB.values()));
console.log(Array.from(mapB.keys()));
const mapA = new Map([[21, 34], [22, 55], [23, 66]]);
console.log(Array.from(mapA));
const mapB = new Map([['101', 'tokyo'], ['202', 'oosaka']]);
console.log(Array.from(mapB.values()));
console.log(Array.from(mapB.keys()));
const mapA = new Map([[21, 34], [22, 55], [23, 66]]); console.log(Array.from(mapA)); const mapB = new Map([['101', 'tokyo'], ['202', 'oosaka']]); console.log(Array.from(mapB.values())); console.log(Array.from(mapB.keys()));
実行結果
> Array [Array [21, 34], Array [22, 55], Array [23, 66]]
> Array ["tokyo", "oosaka"]
> Array ["101", "202"]
> Array [Array [21, 34], Array [22, 55], Array [23, 66]]
> Array ["tokyo", "oosaka"]
> Array ["101", "202"]
> Array [Array [21, 34], Array [22, 55], Array [23, 66]] > Array ["tokyo", "oosaka"] > Array ["101", "202"]