Setting global options should perform a mutating merge

The global options setter was returning a new object after mergeOptions() was converted to be non-mutating. Use lodash's merge() so that the setting changes persist. Add comments to mergeOptions().

src/js/utils/merge-options.js

@@ -3,13 +3,18 @@
  */
 import merge from 'lodash-compat/object/merge';
 
-const isPlain = function(obj) {
+function isPlain(obj) {
   return !!obj
     && typeof obj === 'object'
     && obj.toString() === '[object Object]'
     && obj.constructor === Object;
-};
+}
 
+/**
+ * Merge customizer. video.js simply overwrites non-simple objects
+ * (like arrays) instead of attempting to overlay them.
+ * @see https://lodash.com/docs#merge
+ */
 const customizer = function(destination, source) {
   // If we're not working with a plain object, copy the value as is
   // If source is an array, for instance, it will replace destination
@@ -31,16 +36,25 @@ const customizer = function(destination, source) {
  * Merge one or more options objects, recursively merging **only**
  * plain object properties.  Previously `deepMerge`.
  *
- * @param  {Object} object    The destination object
- * @param  {...Object} source One or more objects to merge into the first
+ * @param  {...Object} source One or more objects to merge
  * @returns {Object}          a new object that is the union of all
  * provided objects
  * @function mergeOptions
  */
 export default function mergeOptions() {
+  // contruct the call dynamically to handle the variable number of
+  // objects to merge
   let args = Array.prototype.slice.call(arguments);
+
+  // unshift an empty object into the front of the call as the target
+  // of the merge
   args.unshift({});
+
+  // customize conflict resolution to match our historical merge behavior
   args.push(customizer);
+
   merge.apply(null, args);
+
+  // return the mutated result object
   return args[0];
 }

src/js/video.js

@@ -142,7 +142,7 @@ videojs.options = createDeprecationProxy(globalOptions, {
  * @method setGlobalOptions
  */
 videojs.setGlobalOptions = function(newOptions) {
-  return mergeOptions(globalOptions, newOptions);
+  return merge(globalOptions, newOptions);
 };
 
 /**
@@ -264,7 +264,7 @@ videojs.TOUCH_ENABLED = browser.TOUCH_ENABLED;
 videojs.extends = extendsFn;
 
 /**
- * Merge two options objects recursively
+ * Merge options objects recursively
  * Performs a deep merge like lodash.merge but **only merges plain objects**
  * (not arrays, elements, anything else)
  * Other values will be copied directly from the second object.
@@ -288,9 +288,7 @@ videojs.extends = extendsFn;
  *     // result.bar.b = [4,5,6];
  * ```
  *
- * @param {Object} The options object whose values will be overriden
- * @param {Object} The options object with values to override the first
- * @param {Object} Any number of additional options objects
+ * @param  {...Object} source One or more objects to merge
  *
  * @return {Object} a new object with the merged values
  * @mixes videojs

test/unit/video.test.js

@@ -59,6 +59,15 @@ test('should add the value to the languages object with lower case lang code', f
   deepEqual(result, globalOptions['languages'][code.toLowerCase()], 'should also match');
 });
 
+test('should allow setting global options', function() {
+  videojs.setGlobalOptions({
+    nonsense: true
+  });
+
+  equal(videojs.getGlobalOptions().nonsense, true, 'set the new option');
+  deepEqual(videojs.options, videojs.getGlobalOptions(), 'updated the options property');
+});
+
 test('should expose plugin registry function', function() {
   var pluginName, pluginFunction, player;