Deprecate lodash.mixxx.js, and script.deepMerge

res/controllers/common-controller-scripts.js

@@ -158,14 +158,15 @@ const isSimpleObject = function(obj) {
     return obj !== null && typeof obj === "object" && obj.constructor.name === "Object";
 };
 
-script.isSimpleObject = isSimpleObject;
-
 /**
  * Deeply merges 2 objects (Arrays and Objects only, not Map for instance).
  * @param target {object | Array} Object to merge source into
  * @param source {object | Array} Object to merge into source
+ * @deprecated Use {@link Object.assign} instead
  */
-const deepMerge = function(target, source) {
+script.deepMerge = function(target, source) {
+    console.warn("script.deepMerge is deprecated; use Object.assign instead");
+
     if (target === source || target === undefined || target === null || source === undefined || source === null) {
         return;
     }
@@ -190,8 +191,6 @@ const deepMerge = function(target, source) {
     }
 };
 
-script.deepMerge = deepMerge;
-
 // ----------------- Mapping constants ---------------------
 
 // Library column value, which can be used to interact with the CO for "[Library] sort_column"

res/controllers/lodash.mixxx.js

@@ -8,6 +8,12 @@
  * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
  */
 ;(function() {
+  const DEPRECATION_MSG = (
+      "Lodash is deprecated and will be removed in a future release of Mixxx; refer to the page " +
+      "https://github.com/mixxxdj/mixxx/wiki/Lodash-Migration for migrations instructions"
+  );
+
+  console.warn(DEPRECATION_MSG);
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
@@ -17068,8 +17074,17 @@
   /*--------------------------------------------------------------------------*/
 
   // Export lodash.
+  /**
+   * @deprecated since 2.5.0
+   * @global
+   */
   var _ = runInContext();
 
   // Export to the global object.
-  root._ = _;
+  Object.defineProperty(root, "_", {
+    get() {
+      console.warn(DEPRECATION_MSG);
+      return _;
+    }
+  })
 }.call(this));

res/controllers/midi-components-0.0.js

@@ -651,7 +651,13 @@
             // Unset isShifted for each ComponentContainer recursively
             this.isShifted = false;
         },
+        /**
+         * @param newLayer Layer to apply to this
+         * @param reconnectComponents Whether components should be reconnected or not
+         * @deprecated since 2.5.0. Use @{ComponentContainer#setLayer} instead
+         */
         applyLayer: function(newLayer, reconnectComponents) {
+            console.warn("ComponentContainer.applyLayer is deprecated; use ComponentContainer.setLayer instead");
             if (reconnectComponents !== false) {
                 reconnectComponents = true;
             }
@@ -670,6 +676,30 @@
                 });
             }
         },
+        /**
+         * @param newLayer Layer to apply to this
+         * @param reconnectComponents Whether components should be reconnected or not
+         */
+        setLayer(newLayer, reconnectComponents) {
+            if (reconnectComponents !== false) {
+                reconnectComponents = true;
+            }
+            if (reconnectComponents === true) {
+                this.forEachComponent(function(component) {
+                    component.disconnect();
+                });
+            }
+
+            Object.assign(this, newLayer);
+
+            if (reconnectComponents === true) {
+                this.forEachComponent(function(component) {
+                    component.connect();
+                    component.trigger();
+                });
+            }
+
+        },
         shutdown: function() {
             this.forEachComponent(function(component) {
                 if (component.shutdown !== undefined