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docs(guide/Expressions): added special case for one-time binding of object literals under Value stabilization algorithm

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One time binding of object literals are treated differently than simple expressions. Added a link to Ben Nadel's article describing how object literals's keys are checked for undefined.

Closes #11982
This commit is contained in:
pholly
2015-05-29 14:56:19 -04:00
committed by Peter Bacon Darwin
parent 5d68c763e2
commit 209f4f3e0f
1 changed files with 10 additions and 6 deletions
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docs/content/guide/expression.ngdoc
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@@ -28,13 +28,13 @@ Angular expressions are like JavaScript expressions with the following differenc
* **No Control Flow Statements:** You cannot use the following in an Angular expression:
conditionals, loops, or exceptions.
* **No Function Declarations:** You cannot declare functions in an Angular expression,
even inside `ng-init` directive.
* **No RegExp Creation With Literal Notation:** You cannot create regular expressions
* **No RegExp Creation With Literal Notation:** You cannot create regular expressions
in an Angular expression.
* **No Comma And Void Operators:** You cannot use `,` or `void` in an Angular expression.
* **Filters:** You can use {@link guide/filter filters} within expressions to format data before
@@ -175,7 +175,7 @@ expression, delegate to a JavaScript method instead.
## No function declarations or RegExp creation with literal notation
You can't declare functions or create regular expressions from within AngularJS expressions. This is
to avoid complex model transformation logic inside templates. Such logic is better placed in a
to avoid complex model transformation logic inside templates. Such logic is better placed in a
controller or in a dedicated filter where it can be tested properly.
## `$event`
@@ -303,10 +303,14 @@ then the expression is not fulfilled and will remain watched.
keep dirty-checking the watch in the future digest loops by following the same
algorithm starting from step 1
#### Special case for object literals
Unlike simple values, object-literals are watched until every key is defined.
See http://www.bennadel.com/blog/2760-one-time-data-bindings-for-object-literal-expressions-in-angularjs-1-3.htm
### How to benefit from one-time binding
If the expression will not change once set, it is a candidate for one-time binding.
If the expression will not change once set, it is a candidate for one-time binding.
Here are three example cases.
When interpolating text or attributes: