How "==" works in JavaScript?

Question

I found == is little confusing for newbies, So I want someone to explain how it works.

For example -

new String("a") == "a" and "a" == new String("a") are both true.
new String("a") == new String("a") is false.

Why?

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators — gherkins, Sep 20 '13 at 14:40
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Expressions_and_Operators — CharliePrynn, Sep 20 '13 at 14:40

score 1 · Answer 1 · answered Sep 20 '13 at 14:41

1

== is called comparison/equality operator, it compares 2 values, but not their data types so for example

1 == '1' will return true, for stricter comparison, use === which will compare the data types too so 1 === '1' will return false

answered Sep 20 '13 at 14:41

Mr. Alien

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score 0 · Answer 2 · answered Sep 20 '13 at 14:42

== is a comparison operator that means "equal to" but does not take variable typing into account.

=== is a stricter comparison operator that means "equal to and same type".

So if you have a string called numberStr with a value of 2 and an integer called numberInt with a value of 2, they will evaluate as follows:

numberStr == numberInt  // evaluates to true
numberStr === numberInt // evaluates to false because types are different

How "==" works in JavaScript?

2 Answers2