Why angular is behaving unexpected with different strings?

Question

I have started learning angular JS. I confused with very basic.

What I am doing: I am playing with 2 string postNumber123 and 123preNumber.
angular showing error for string start with number, and ignoring if string start with characters.
I just wanted to know in deep what is the resone behaind it? or I am missing something?

Angular ignoring this error:

<div ng-app="" >
     <div> Testing : {{ postNumber123 }} </div>  <!-- ignoring error --> 
    <div>After execution : {{ 3+4 }} </div>
</div>

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="" >
    
    <!-- <div> Testing : {{ 123preNumber }} </div> --> <!-- showing error -->
    
     <div> Testing : {{ postNumber123 }} </div>  <!-- ignoring error --> 
    
    <div>After execution : {{ 3+4 }} </div>
    
</div>

Showing error for this:

<div ng-app="" >
    <div> Testing : {{ 123preNumber }} </div> <!-- showing error -->
    <div>After execution : {{ 3+4 }} </div>
</div>

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="" >
        <div> Testing : {{ 123preNumber }} </div> <!-- showing error -->
        
        <!-- <div> Testing : {{ postNumber123 }} </div> --> <!-- ignoring error --> 
        
        <div>After execution : {{ 3+4 }} </div>
        
    </div>

Thanks!

score 4 · Accepted Answer · edited May 23 '17 at 12:29

4

123preNumber is not a valid variable because it starts with a number, use postNumber123 instead. See here for more details why.

edited May 23 '17 at 12:29

Community

1
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answered Jul 24 '15 at 14:56

nico

2,022
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Thanks I got it, It means that the angular find the variable, in case variable does not defind, angular ignore it and execute next. In my case angular directly pointing this is not valid js variable. – Sachink Jul 24 '15 at 15:12

score 3 · Answer 2 · answered Jul 24 '15 at 14:56

3

123preNumber isn't a valid JS expression.

postNumber123 is a valid JS variable name.

answered Jul 24 '15 at 14:56

Dave Newton

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score 0 · Answer 3 · answered Jul 24 '15 at 16:22

0

variable name always start from all alphabetic, _, $ in mostly computer language and same validation apply with AngularJS. so make sure when declare any variable.

answered Jul 24 '15 at 16:22

Sandeep

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Why angular is behaving unexpected with different strings?

3 Answers3