javascript - Syntax for conditional one-way binding in ng-if expression in Angular JS - Stack Overflow

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I know the syntax for one-way binding inside ng-if looks like this:

<div ng-if="::vm.user.loggedIn"></div> 

(from here)

But what's the syntax if I want to use one-way binding with the not operator? I've tried something like

<div ng-if="!::vm.user.loggedIn"></div>

or

<div ng-if="::!vm.user.loggedIn"></div> 

No luck. Any ideas?

I know the syntax for one-way binding inside ng-if looks like this:

<div ng-if="::vm.user.loggedIn"></div> 

(from here)

But what's the syntax if I want to use one-way binding with the not operator? I've tried something like

<div ng-if="!::vm.user.loggedIn"></div>

or

<div ng-if="::!vm.user.loggedIn"></div> 

No luck. Any ideas?

• javascript
• angularjs

Share Improve this question Follow edited Nov 18, 2015 at 20:08 DJ. 6,78411 gold badge3535 silver badges4949 bronze badges asked Nov 18, 2015 at 20:06 Paul ErdosPaul Erdos 1,37522 gold badges2323 silver badges4949 bronze badges 1

• I just tried, and ng-if="::!vm.user.loggedIn" works for me: jsfiddle/858tk3nn – Josh Crozier Commented Nov 18, 2015 at 20:19

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2 Answers 2

Sorted by: Reset to default 5

Try:

<div ng-if="::(!vm.user.loggedIn)"></div>

Demo Plunkr:

http://plnkr.co/edit/ZcV3yxTiERtPiPlMJb2L?p=preview

It's not one-way binding, but one time binding that you are talking about. One time bindings only use the first value, and then never update.

However, <div ng-if="::!vm.user.loggedIn"></div> is pletely valid and should work correctly. See this plunker for example: http://plnkr.co/edit/o1va21WuuAykFRTBOGRT?p=preview

The internal code angular uses doesn't do anything special to the expression, aside from stripping off the two colons at the start and changing a oneTime boolean. My guess is that you have some other logic (probably asynchronous) that determines vm.user.loggedIn and the 1 time binding uses the initial value, then does not update, or there is some other error preventing the code from working.

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