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    Array.isArray()

    Summary

    The Array.isArray() method returns true if an object is an array, false if it is not.

    Syntax

    Array.isArray(obj)

    Parameters

    obj
    The object to be checked.

    Description

    See the article “Determining with absolute accuracy whether or not a JavaScript object is an array” for more details.

    Examples

    // all following calls return true
    Array.isArray([]);
    Array.isArray([1]);
    Array.isArray(new Array());
    // Little known fact: Array.prototype itself is an array:
    Array.isArray(Array.prototype); 
    
    // all following calls return 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({ __proto__: Array.prototype });
    

    Polyfill

    Running the following code before any other code will create Array.isArray() if it's not natively available.

    if (!Array.isArray) {
      Array.isArray = function(arg) {
        return Object.prototype.toString.call(arg) === '[object Array]';
      };
    }
    

    Specifications

    Specification Status Comment
    ECMAScript 5.1 (ECMA-262)
    The definition of 'Array.isArray' in that specification.
    Standard Initial definition. Implemented in JavaScript 1.8.5.
    ECMAScript 6 (ECMA-262)
    The definition of 'Array.isArray' in that specification.
    Release Candidate  

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support 5 4.0 (2.0) 9 10.5 5
    Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support (Yes) (Yes) 4.0 (2.0) (Yes) (Yes) (Yes)

    Based on Kangax's compat table.

    See also

    Document Tags and Contributors

    Last updated by: SphinxKnight,
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