Appropriate usage of == and === in JavaScript [duplicate]

Question

I'm new to Java Script What is the exact difference between (== Vs ===, != Vs !==, etc) in JavaScript? Have read some articles and wanted to be more clear on this. Thanks in advance.

if a function returns multiple values that are equivalent to false like 0, '0' or false (for example 0 means no result and false and error) and you want them to be treated the same then you can use == but if you want them to be treated differently then you have to use ===. — My1
– My1, Commented Nov 13, 2015 at 10:39

Paul S. · Accepted Answer · 2014-04-14 21:18:02Z

3

The == operator means equality after type conversion

1 == '1';  // true
1 == 1;    // true

The === operator means equality without any conversion

1 === '1'; // false
1 === 1;   // true

edited Apr 14, 2014 at 21:18

Paul S.

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answered Apr 14, 2014 at 21:07

Timigen

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3 Comments

user890167 Over a year ago

Ah so that's why ",,," == new Array(4); returns true... :/

Zini Over a year ago

!= and !== do the same thing but consider inequality of values converted and of types.

Anchit Over a year ago

'==' is used to compare only values. '===' is used to compare both value and type of the variable being compared. Both return a boolean value as result based on the comparison.

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