JavaScript quiz. Consider foolowing code snippet: <pre><code class=

Consider foolowing code snippet:

var arr =[];

How can you check if arr is array? Select all correct options.

Explanation

1) if (arr) {}; // check if the object exists
2) if (arr.splice){}; // we can check whether element has a splice() method that can have only array.
3) Array.isArray(arr) // check using function isArray();
4) if (arr.constructor === Array) // check throught contstructor;
5) typeof(arr); // will return object
6) arr instanceof Array - tests whether an object has in its prototype chain of Array object

arrays

4 Comments

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@basimdev32 agree! But in some cases can be used, but probably wouldn't be good choice

2018 Feb 4, 5:52:54 PM

@nklskr20 thanks! fixed

2018 Feb 4, 5:51:54 PM

Of cause not only Array has splice method. For example, function MyClass(){ this.splice = 12; } any instance of MyClass will have splice property as well.

2018 Jan 28, 2:24:53 PM

The explanation has russian words.

2018 Jan 26, 5:07:48 AM

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