Is it correct to use obj.constructor === Array to test if an object is an array as suggested here? Does it always returns correct answer compatible with Array.isArray?
1 Answer
Depends, there are a few scenarios where it can return a different value, but Array.isArray will work.
The Array object for one window is not the the same Array object in another window.
var obj = someIframe.contentWindow.someArray;
console.log(obj.constructor === Array);//false
console.log(Array.isArray(obj));//true
The constructor property can be overwritten.
var obj = [];
obj.constructor = null;
console.log(obj.constructor === Array);//false
console.log(Array.isArray(obj));//true
Another object can also set the constructor property to Array.
var obj = {};
obj.constructor = Array;
console.log(obj.constructor === Array);//true
console.log(Array.isArray(obj));//false
answered Feb 12, 2015 at 0:49
Alexander O'Mara
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obj.constructor === Classas well.