Fix MediaError

src/js/media-error.js

@@ -4,24 +4,45 @@
 import assign from 'object.assign';
 
 /*
- * Custom MediaError to mimic the HTML5 MediaError
+ * Custom MediaError class which mimics the standard HTML5 MediaError class.
  *
- * @param {Number} code The media error code
+ * @param {Number|String|Object|MediaError} value
+ *        This can be of multiple types:
+ *        - Number: should be a standard error code
+ *        - String: an error message (the code will be 0)
+ *        - Object: arbitrary properties
+ *        - MediaError (native): used to populate a video.js MediaError object
+ *        - MediaError (video.js): will return itself if it's already a
+ *          video.js MediaError object.
  */
-let MediaError = function(code){
-  if (typeof code === 'number') {
-    this.code = code;
-  } else if (typeof code === 'string') {
+function MediaError(value) {
+
+  // Allow redundant calls to this constructor to avoid having `instanceof`
+  // checks peppered around the code.
+  if (value instanceof MediaError) {
+    return value;
+  }
+
+  if (typeof value === 'number') {
+    this.code = value;
+  } else if (typeof value === 'string') {
     // default code is zero, so this is a custom error
-    this.message = code;
-  } else if (typeof code === 'object') { // object
-    assign(this, code);
+    this.message = value;
+  } else if (typeof value === 'object') {
+
+    // We assign the `code` property manually because native MediaError objects
+    // do not expose it as an own/enumerable property of the object.
+    if (typeof value.code === 'number') {
+      this.code = value.code;
+    }
+
+    assign(this, value);
   }
 
   if (!this.message) {
     this.message = MediaError.defaultMessages[this.code] || '';
   }
-};
+}
 
 /*
  * The error code that refers two one of the defined

src/js/player.js

@@ -2277,12 +2277,7 @@ class Player extends Component {
       return this;
     }
 
-    // error instance
-    if (err instanceof MediaError) {
-      this.error_ = err;
-    } else {
-      this.error_ = new MediaError(err);
-    }
+    this.error_ = new MediaError(err);
 
     // add the vjs-error classname to the player
     this.addClass('vjs-error');

src/js/tech/tech.js

@@ -282,11 +282,7 @@ class Tech extends Component {
    */
   error(err) {
     if (err !== undefined) {
-      if (err instanceof MediaError) {
-        this.error_ = err;
-      } else {
-        this.error_ = new MediaError(err);
-      }
+      this.error_ = new MediaError(err);
       this.trigger('error');
     }
     return this.error_;

test/unit/media-error.test.js

@@ -0,0 +1,65 @@
+/* eslint-env qunit */
+import window from 'global/window';
+import MediaError from '../../src/js/media-error';
+
+/**
+ * Creates a real native MediaError object.
+ *
+ * @param  {Number} code
+ * @param  {String} [message]
+ * @return {MediaError}
+ */
+const createNativeMediaError = (code, message) => {
+  const err = Object.create(window.MediaError);
+
+  Object.defineProperty(err, 'code', {value: code});
+
+  if (message) {
+    err.message = message;
+  }
+
+  return err;
+};
+
+QUnit.module('MediaError');
+
+QUnit.test('can be constructed from a number', function(assert) {
+  const mediaError = new MediaError(1);
+
+  assert.strictEqual(mediaError.code, 1);
+  assert.strictEqual(mediaError.message, MediaError.defaultMessages['1']);
+});
+
+QUnit.test('can be constructed from a string', function(assert) {
+  const mediaError = new MediaError('hello, world');
+
+  assert.strictEqual(mediaError.code, 0);
+  assert.strictEqual(mediaError.message, 'hello, world');
+});
+
+QUnit.test('can be constructed from an object', function(assert) {
+  const mediaError = new MediaError({code: 2});
+  const mediaErrorMsg = new MediaError({code: 2, message: 'hello, world'});
+
+  assert.strictEqual(mediaError.code, 2);
+  assert.strictEqual(mediaError.message, MediaError.defaultMessages['2']);
+  assert.strictEqual(mediaErrorMsg.code, 2);
+  assert.strictEqual(mediaErrorMsg.message, 'hello, world');
+});
+
+QUnit.test('can be constructed from a native MediaError object', function(assert) {
+  const mediaError = new MediaError(createNativeMediaError(3));
+  const mediaErrorMsg = new MediaError(createNativeMediaError(4, 'hello, world'));
+
+  assert.strictEqual(mediaError.code, 3);
+  assert.strictEqual(mediaError.message, MediaError.defaultMessages['3']);
+  assert.strictEqual(mediaErrorMsg.code, 4);
+  assert.strictEqual(mediaErrorMsg.message, 'hello, world');
+});
+
+QUnit.test('can be constructed redundantly', function(assert) {
+  const mediaError = new MediaError(2);
+  const redundantMediaError = new MediaError(mediaError);
+
+  assert.strictEqual(redundantMediaError, mediaError);
+});