Minor code cleanups, e.g. utilizing arrow functions

Change-Id: I56bcfa040553a96f018f22483f3f988c5639fc97

src/container.js

@@ -83,7 +83,7 @@ export default function createContainer() {
 			}
 
 			if ( !Object.prototype.hasOwnProperty.call( cache, name ) ) {
-				cache[ name ] = factories[ name ]( this );
+				cache[ name ] = factory( this );
 			}
 
 			return cache[ name ];

src/instrumentation/eventLogging.js

@@ -23,16 +23,7 @@ export function isEnabled( user, config, window ) {
 		return true;
 	}
 
-	if ( !config.get( 'wgPopupsEventLogging' ) ) {
+	return config.get( 'wgPopupsEventLogging' ) &&
-		return false;
+		window.navigator &&
-	}
+		typeof window.navigator.sendBeacon === 'function';
-
-	if (
-		!window.navigator ||
-		typeof window.navigator.sendBeacon !== 'function'
-	) {
-		return false;
-	}
-
-	return true;
 }

src/ui/templates/referencePreview/referencePreview.js

@@ -66,7 +66,7 @@ export function renderReferencePreview(
 	} );
 
 	// We assume elements that benefit from being collapsible are to large for the popup
-	$el.find( '.mw-collapsible' ).replaceWith( () => $( '<div>' )
+	$el.find( '.mw-collapsible' ).replaceWith( $( '<div>' )
 		.addClass( 'mwe-collapsible-placeholder' )
 		.append(
 			$( '<span>' )

tests/node-qunit/changeListeners/footerLink.test.js

@@ -32,9 +32,7 @@ QUnit.module( 'ext.popups/changeListeners/footerLink @integration', {
 			this.footerLinkChangeListener( undefined, this.state );
 		};
 
-		this.getLink = function () {
+		this.getLink = () => this.$footer.find( 'li:last-child' );
-			return this.$footer.find( 'li:last-child' );
-		};
 	},
 	afterEach() {
 		this.$footer.remove();

tests/node-qunit/instrumentation/eventLogging.test.js

@@ -15,13 +15,7 @@ QUnit.module( 'ext.popups/instrumentation/eventLogging', {
 		this.user = stubs.createStubUser();
 
 		// Helper function that DRYs up the tests below.
-		this.isEnabled = function () {
+		this.isEnabled = () => isEnabled( this.user, this.config, this.window );
-			return isEnabled(
-				this.user,
-				this.config,
-				this.window
-			);
-		};
 	}
 } );
 

tests/selenium/pageobjects/popups.page.js

@@ -59,9 +59,7 @@ class PopupsPage extends Page {
 	}
 
 	hasReferencePopupsEnabled() {
-		return browser.execute( function () {
+		return browser.execute( () => mw.config.get( 'wgPopupsReferencePreviews' ) );
-			return mw.config.get( 'wgPopupsReferencePreviews' );
-		} );
 	}
 
 	abandonLink() {