angular.scope.$apply.html

<h1>angular.scope.$apply</h1>
<div class="angular-scope-apply"><h2>Description</h2>
<div class="description"><p><code>$apply()</code> is used to execute an expression in angular from outside of the angular framework.
(For example from browser DOM events, setTimeout, XHR or third party libraries).
Because we are calling into the angular framework we need to perform proper scope life-cycle
of <a href="#!/api/angular.service.$exceptionHandler"><code>exception handling</code></a>,
<a href="#!/api/angular.scope.$digest"><code>executing watches</code></a>.</p>

<h4>Life cycle</h4>

<h3>Pseudo-Code of <code>$apply()</code></h3>

<pre><code>  function $apply(expr) {
    try {
      return $eval(expr);
    } catch (e) {
      $exceptionHandler(e);
    } finally {
      $root.$digest();
    }
  }
</code></pre>

<p>Scope's <code>$apply()</code> method transitions through the following stages:</p>

<ol>
<li>The <a href="#!/guide/dev_guide.expressions">expression</a> is executed using the
<a href="#!/api/angular.scope.$eval"><code>$eval()</code></a> method.</li>
<li>Any exceptions from the execution of the expression are forwarded to the
<a href="#!/api/angular.service.$exceptionHandler"><code>$exceptionHandler</code></a> service.</li>
<li>The <a href="#!/api/angular.scope.$watch"><code>watch</code></a> listeners are fired immediately after the expression
was executed using the <a href="#!/api/angular.scope.$digest"><code>$digest()</code></a> method.</li>
</ol></div>
<h2>Usage</h2>
<div class="usage"><div ng:non-bindable=""><pre class="brush: js; html-script: true;">angular.scope.$apply([exp]);</pre>
</div>
<h3>Parameters</h3>
<ul class="parameters"><li><code ng:non-bindable="">exp<i>(optional)</i> – {(string|function())} – </code>
<p>An angular expression to be executed.</p>

<ul>
<li><code>string</code>: execute using the rules as defined in <a href="#!/guide/dev_guide.expressions">expression</a>.</li>
<li><code>function(scope)</code>: execute the function with current <code>scope</code> parameter.</li>
</ul></li>
</ul>
<h3>Returns</h3>
<div class="returns"><code ng:non-bindable="">{*}</code>
– <p>The result of evaluating the expression.</p></div>
</div>
</div>