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Array.isArray()

20157

Array.isArray()

console.log(Array.isArray([1, 3, 5]));
// Expected output: true

console.log(Array.isArray("[]"));
// Expected output: false

console.log(Array.isArray(new Array(5)));
// Expected output: true

console.log(Array.isArray(new Int16Array([15, 33])));
// Expected output: false

js
Array.isArray(value)

value

value Array true false value TypedArray false

Array.isArray() Array Array Array truecross-realm Array instanceof Array

JavaScript

Array.isArray() Array.prototype instanceof Array

Array.isArray()

js
//  true
Array.isArray([]);
Array.isArray([1]);
Array.isArray(new Array());
Array.isArray(new Array("a", "b", "c", "d"));
Array.isArray(new Array(3));
//  Array.prototype 
Array.isArray(Array.prototype);

//  false
Array.isArray();
Array.isArray({});
Array.isArray(null);
Array.isArray(undefined);
Array.isArray(17);
Array.isArray("Array");
Array.isArray(true);
Array.isArray(false);
Array.isArray(new Uint8Array(32));
//  Array 
Array.isArray({ __proto__: Array.prototype });

instanceof Array.isArray()

Array Array.isArray instanceof Array.isArray

js
const iframe = document.createElement("iframe");
document.body.appendChild(iframe);
const xArray = window.frames[window.frames.length - 1].Array;
const arr = new xArray(1, 2, 3); // [1, 2, 3]

//  Array
Array.isArray(arr); // true
// arr  xArray.prototype Array.prototype 
arr instanceof Array; // false

ECMAScript 2027 LanguageSpecification
# sec-array.isarray


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