Difference in between ! and !! in angular

Question

What is difference in between !!user.rank and !user.rank

<div ng-show="!!user.rank">
    Rank: {{user.rank}}
</div>


<div ng-show="!user.rank">
    <button class="btn btn-success" ng-click="KnightMe(user)">Knight       Me</button>
</div>

score 2 · Answer 1 · answered Mar 09 '17 at 04:26

2

! is not operator
!! casts something to truthy / not truthy

var foo = 0;
console.log(!!foo);
//false

answered Mar 09 '17 at 04:26

GN.

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could you give any reference for !! operator ? – Abdullah Al Noman Mar 09 '17 at 04:30
can we say ! is not operator and !! is for truthy? – Bharat Joshi Mar 09 '17 at 04:35
1

@user3886602 its not an operator its just ! twise .. – Abdullah Al Noman Mar 09 '17 at 04:40

score 1 · Answer 2 · edited May 23 '17 at 12:32

1

! converts Object to boolean. If it was falsey (e.g. 0, null, undefined, etc.), it will be false, otherwise, true.

!oObject  //Inverted boolean
!!oObject //Non inverted boolean so true boolean representation

So !! is not an operator, it's just the ! operator twice

see the detailed question and answer here

edited May 23 '17 at 12:32

Community

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answered Mar 09 '17 at 04:39

Abdullah Al Noman

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@user3886602 mark as answer if this helped :) – Abdullah Al Noman Mar 09 '17 at 05:46

Difference in between ! and !! in angular

2 Answers2