How to call one controller function from another controller function in Lightning?

Question

If I have two functions foo() and bar() in my Lightning component controller, how can I call one function directly from another function, without having to queue it up through $A?

Here's a sample controller setup:

({
    bar : function(component, event, helper) {
        // Do something cool
    },
    foo : function(component, event, helper) {
        // How do I call bar() from here?
    }
})

Answer 1

I think that the better approach would be to try to extract whatever it is that you need to call in that controller function into the helper and call the helper. The helpers exist to enable sharing code within a component. Do you have a use case where that wouldn't work?

Just for fun, inspecting the action object the following would work:

var action = component.get("c.bar");
action.$meth$();

Obviously don't do that! :)

Answer 2

Lightning has been enhanced with a way to call a controller function after this question was posted in 2014.

You can declare the target controller function using the tag aura:method like below:

<aura:method name="barMethod" action="{!c.bar}" description="bar controller function" />

Then you can reference it on the controller:

({ bar : function(component, event, helper) { // Do something cool }, foo : function(component, event, helper) { // This is how you call bar() from here component.barMethod(); } })

If you need to pass a parameter other than those 3, you'll need to add an aura:attribute tag to the aura:method:

<aura:method name="barMethod" action="{!c.bar}" description="bar controller function"> <aura:attribute name="param1" type="the type" default="default value" /> </aura:method>

And the bar function needs to extract the parameter from the event like below:

var params = event.getParam( 'arguments' ); if( params ) { var param1 = params.param1; // rest of the code here }

See more at: Calling Component Methods

Answer 3

This is why Helpers exist as Peter correctly outlined above. We do know that there are a number of patterns in Aura that appear heavyweight but most have a logical justification. This specific case is one where I have a hard time explaining the why and we do have plans to streamline a number of things like this in the future (no ETA but I can say that we have the same complaint inside of Salesforce R&D).

You do not pass helper directly - Aura does that for you - this is just dependency injection which is a common pattern in many frameworks e.g. Angular.js

Answer 4

Reworking your specific sample:

myController.js

({
    bar : function(component, event, helper) {
        helper.doSomethingCool();
    },
    foo : function(component, event, helper) {
         helper.doSomethingCool();
    }
})

myHelper.js

({
    somethingCool : function() {
        // Do something cool
    }
})

Answer 5

In the case where you have Button1 that on click calls foo and Button2 that on click should do all that foo does and something else you'd call it like this:

bar: function(component, event, helper) {
    //do bar
    component.get("c.foo").run();
}