Add two new core methods to allow invoking possibly unknown methods on objects if they exist

[devinus]

Rationale:

This is such a common idiom throughout Ember and my Ember apps:

var foo = get(this, 'foo');
if (foo && typeof foo.bar === 'function') {
  foo.bar();
}

...that I think it makes perfect sense to solidify the paradigm in Ember, especially when the code is less than 10 lines long total. Great code exposing good patterns in small chunks feels like the new thing Ember is trying to achieve. For instance: Ember.Evented.

I ask for naming suggestions as I don't particularly like tryToPerform.

Two possible alternatives already suggested include:

• methodExists / invokeIfExists
• canInvoke / tryInvoke

[travisbot]

This pull request passes (merged 3429efff into 1f8c983).

[travisbot]

This pull request passes (merged 4d4c36d7 into 1f8c983).

[jbrown]

Do you have some links to places where this idiom exists in the Ember source?

[devinus]

@jbrown Sure. Take a look here: http://cloud.github.com/downloads/emberjs/ember.js/ember-latest.js

Do a Ctrl-F for "=== 'function'" or "'function' ==="

[devinus]

Any more discussion on the names?

[pangratz]

👍

[devinus]

Renamed to canInvoke/tryInvoke as per @kselden's suggestion. These names are closer to existing Ember conventions, e.g trySetPath.

[travisbot]

This pull request passes (merged 2ffe666 into 20fb175).

[joliss]

For anyone using CoffeeScript, you can always write this:

@get('foo')?.bar?()

to yield

var _ref;

if ((_ref = this.get('foo')) != null) { // != checks for null or undefined
  if (typeof _ref.bar === "function") _ref.bar();
}