Angular.js: Using multiple one time binded expression in ng-if throws error

Created on 22 Mar 2015 · 3Comments · Source: angular/angular.js

I have my code as follows:

one_time.js

var sample = angular.module('sample', []);

sample.controller('OneTimeController', function () {
    this.name = 'John';
    this.blah = 'sdflk';
});

index.html
<!DOCTYPE html>
<html>

<head>
  <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
  <script type="text/javascript" src="one_time.js"></script>
</head>

<body ng-app="sample">
<div ng-controller="OneTimeController as test">
  <p>Input something in the input box:</p>
  <p>Name: <input type="text" ng-model="test.name" value="John"></p>
  <p ng-bind="test.name"></p>
  <p ng-bind="::test.name"></p>
  <p ng-if="test.name && test.blah">testing</p> <!-- works perfectly-->
  <p ng-if="::test.name && test.blah">testing with first expression as one time binded</p> <!-- works but the second property is not one time binded-->
  <p ng-if="::test.name && ::test.blah">testing with one time bind</p><!-- doesn't work throws syntax error-->

</div>
</body>
</html>

I am trying to show a  tag with an ng-if condition in which I want name property to be one time binded. I already know that it'll not change so wanted to try one time binding in ng-if also. It works perfectly when I don't use one time binding or when I only use one time binding with the first expression in this case testing with first expression as one time binded, however when I try to use one time binding in more than one expression coupled with a guard operator it throws me error as syntax error:

Error: [$parse:syntax] Syntax Error: Token ':' not a primary expression at column 14 of the expression [test.name && ::test.blah && ::test.blah] starting at [::test.blah && ::test.blah].
http://errors.angularjs.org/1.3.14/$parse/syntax?

Is this a bug or genuine syntax error ? I am using angularjs version 1.3.14.

Source

ashish91

👍1

Most helpful comment

I think You should use () for on-time-bindings with expressions ex.:testing with first expression as one time binded

piernik on 22 Mar 2015

👍7

All 3 comments

I think You should use () for on-time-bindings with expressions ex.:testing with first expression as one time binded

piernik on 22 Mar 2015

👍7

@piernik Thanks works like a charm. I was trying (::test.name) && (::test.blah) but it seems like the very first :: activates one time binding. :+1:

ashish91 on 22 Mar 2015

one time binding (::) applies to all the expressions used within the ng-if.
 is same as 

Unfortunately we cannot mix one time binding with one way binding expressions in a single expression in angular js.