Array.prototype.flat and Array.prototype.flatMap · V8

Show navigation Array.prototype.flat #The array in this example is several levels deep: it contains an array which in turn contains another array. const array = [1, [2, [3]]]; // ^^^^^^^^^^^^^ outer array // ^^^^^^^^ inner array // ^^^ innermost arrayArray#flat returns a flattened version of a given array. array.flat(); // → [1, 2, [3]] // …is equivalent to: array.flat(1); // → [1, 2, [3]]The defa

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ES2019で入る予定のArray#flatとArray#flatMapの使い方について