Why These javascript expressions works unexpectedly

Question

There are some javascript syntaxes and I didnt understand why they works.

1.

({} === {}) // returns false

2.

function foo() {
       return
       {
          foo: 'bar'
       }
    }

    function bar() {
       return {
          foo: 'bar'
       }
    }

(typeof foo() === typeof bar()) //return false again

3.

([1,2,3] == [1,2,3]); //very interesting false again

First and Third: Cannot compare array & objects with `===`. Second: Automatic Semicolon Insertion. — Tushar, Jun 05 '17 at 09:02
https://developer.mozilla.org/en/docs/Web/JavaScript/Equality_comparisons_and_sameness — Suraj Rao, Jun 05 '17 at 09:05

score 1 · Answer 1 · answered Jun 05 '17 at 09:04

1

In all of these cases, a reference check is performed on the objects on the left and right hand side of the comparison operator. This returns false because although they look the same, they are actually different instances.

answered Jun 05 '17 at 09:04

Lew

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8
13

Save for #2 (see Tushar's comment) – Álvaro González Jun 05 '17 at 09:12

Why These javascript expressions works unexpectedly

1 Answers1