LockerService not allowing subscribing to $A.logger

Question

I have made a test Lightning app to figure out why error catching isn't working as I expected.

Component:

<aura:handler name="init" value="{!this}" action="{!c.doInit}" />

</aura:component>

Controller:

({
    // Handle component initialization
    doInit : function(component, event, helper) {
        $A.logger.subscribe("INFO", logCustom);
        $A.log('initialized logger');

        function logCustom(level, message, error) {
            console.log(getTimestamp());
            console.log(error);
            console.log(error.stack)
        }

        function getTimestamp() {
            return new Date().toJSON();
        }

    }

})

Error:

"Something has gone wrong. Error during init [Action failed: c$JQTest$controller$doInit [TypeError: Cannot read property 'subscribe' of undefined]]"

heroku lightning:lint

  error       aura-api     Invalid Aura API                    
  Line:4:9
          $A.logger.subscribe("INFO", logCustom);
           ^

Perhaps I'm super confused... is $A.logger no longer supported? If not what is the new preferred way to catch errors? Thanks!

Answer 1

With locker being activated you will not be able to use the undocumented API's and this was one of the reason why locker is in place

See the JavaScript API to find available methods and objects at https://myDomain.lightning.force.com/auradocs/reference.app, where myDomain is the name of your custom Salesforce domain.

The correct way to log the errors has been documented in release guide

<!--c:recoverableError-->
<aura:component>
<p>Click the button to trigger the controller to throw an error.</p>
<div aura:id="div1"></div>

<ui:button label="Throw an Error" press="{!c.throwErrorForKicks}"/>

The JS controller side function is as below

/*recoverableErrorController.js*/
 ({
    throwErrorForKicks: function(cmp) {
    // this sample always throws an error to demo try/catch
    var hasPerm = false;
    try {
        if (!hasPerm) {
            throw new Error("You don't have permission to edit this record.");
        }
    }
    catch (e) {
        $A.createComponents([
            ["ui:message",{
                "title" : "Sample Thrown Error",
                "severity" : "error",
            }],
            ["ui:outputText",{
                "value" : e.message
            }]
            ],
            function(components, status){
                if (status === "SUCCESS") {
                    var message = components[0];
                    var outputText = components[1];
                    // set the body of the ui:message to be the ui:outputText
                    message.set("v.body", outputText);
                    var div1 = cmp.find("div1");
                    // Replace div body with the dynamic component
                    div1.set("v.body", message);
                }
            }
        );
    }
  }
})