Evaluating Javascript Expressions

Question

I was trying to update the image being displayed after an image file with same name overwrote the previous file and came across this link:Reload/refresh an element(image) in jQuery

I had a scope element "imgUrl" which I was passing in the data-ng-src as:

<img data-ng-src="{{imageUrl + '?' + GetTimeStamp()}}">

This thing worked but I also tried this:

<img data-ng-src="{{imageUrl}} + '?' + {{GetTimeStamp()}}">

And this didn't work. Whats the difference between these two expressions?

Kazimieras · Accepted Answer · 2016-06-10 09:58:58Z

3

The opening brackets {{ indicate that an angular expression begins, and the closing brackets }} indicate that it ends. Everything outside of the brackets is considered to be a plain text attribute. Therefore, the + becomes just a text symbol between the two expressions, rather than acting as the string concatenation operator.

edited Jun 10, 2016 at 9:58

answered Jun 10, 2016 at 9:51

Kazimieras

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5 Comments

Sergio Tulentsev Over a year ago

"Everything, that follows the closing brackets" - to be precise, it's "everything outside of {{ }}"

Kazimieras Over a year ago

@SergioTulentsev You are right, that was rather ambiguous, since anything can follow the brackets. Edited the answer. Thank you!

Vishal Chugh Over a year ago

@Kazimieras And if I hadn't used + and just this: {{imageUrl}}?{{GetTimeStamp()}}. Had it been fine?

Kazimieras Over a year ago

@VishalChugh This is also fine. In this case you are just evaluating two simpler expressions instead of a more complex one.

Kazimieras Over a year ago

@VishalChugh if you find that your question has been answered, it would be great if you could mark it as accepted :)

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