refactor: remove extend() and tests (#7950)

BREAKING CHANGE: This removes the videojs.extend() method, please use ES6 classes instead.

src/js/extend.js

@@ -1,78 +0,0 @@
-/**
- * @file extend.js
- * @module extend
- */
-
-import _inherits from '@babel/runtime/helpers/inherits';
-import log from './utils/log';
-
-/**
- * Used to subclass an existing class by emulating ES subclassing using the
- * `extends` keyword.
- *
- * @function
- * @deprecated
- * @example
- * var MyComponent = videojs.extend(videojs.getComponent('Component'), {
- *   myCustomMethod: function() {
- *     // Do things in my method.
- *   }
- * });
- *
- * @param    {Function} superClass
- *           The class to inherit from
- *
- * @param    {Object}   [subClassMethods={}]
- *           Methods of the new class
- *
- * @return   {Function}
- *           The new class with subClassMethods that inherited superClass.
- *
- * @deprecated videojs.extend() is deprecated as of v8; use native ES6 classes instead
- */
-const extend = function(superClass, subClassMethods = {}) {
-  log.warn('The extend() method is deprecated. Please use native ES6 classes instead.');
-
-  const isNativeClass = superClass && /^class/.test(superClass.toString());
-
-  let subClass = function() {
-    superClass.apply(this, arguments);
-  };
-
-  // If the provided super class is a native ES6 class,
-  // make the sub class one as well.
-  if (isNativeClass) {
-    subClass = class SubClass extends superClass {};
-  }
-
-  let methods = {};
-
-  if (typeof subClassMethods === 'object') {
-    if (subClassMethods.constructor !== Object.prototype.constructor) {
-      subClass = subClassMethods.constructor;
-    }
-    methods = subClassMethods;
-  } else if (typeof subClassMethods === 'function') {
-    subClass = subClassMethods;
-  }
-
-  if (!isNativeClass) {
-    _inherits(subClass, superClass);
-  }
-
-  // this is needed for backward-compatibility and node compatibility.
-  if (superClass) {
-    subClass.super_ = superClass;
-  }
-
-  // Extend subObj's prototype with functions and other properties from props
-  for (const name in methods) {
-    if (methods.hasOwnProperty(name)) {
-      subClass.prototype[name] = methods[name];
-    }
-  }
-
-  return subClass;
-};
-
-export default extend;

src/js/video.js

@@ -31,7 +31,6 @@ import * as Dom from './utils/dom.js';
 import * as browser from './utils/browser.js';
 import * as Url from './utils/url.js';
 import * as Obj from './utils/obj';
-import extend from './extend.js';
 import xhr from '@videojs/xhr';
 
 // Include the built-in techs
@@ -359,15 +358,6 @@ videojs.browser = browser;
  */
 videojs.obj = Obj;
 
-/**
- * Deprecated reference to the {@link module:extend~extend|extend function}
- *
- * @type {Function}
- * @see {@link module:extend~extend|extend}
- * @deprecated Deprecated and will be removed in 9.0. Please use native ES6 classes instead.
- */
-videojs.extend = deprecateForMajor(9, 'videojs.extend', 'native ES6 classes', extend);
-
 /**
  * Deprecated reference to the {@link module:obj.merge|merge function}
  *

test/unit/extend.test.js

@@ -1,55 +0,0 @@
-/* eslint-env qunit */
-import extend from '../../src/js/extend.js';
-
-QUnit.module('extend.js');
-
-QUnit.test('should add implicit parent constructor call', function(assert) {
-  assert.expect(4);
-
-  let superCalled = false;
-
-  [
-    function() {
-      superCalled = true;
-    },
-    class Parent {
-      constructor() {
-        superCalled = true;
-      }
-    }
-  ].forEach(Parent => {
-    const Child = extend(Parent, {
-      foo: 'bar'
-    });
-    const child = new Child();
-
-    assert.ok(superCalled, 'super constructor called');
-    assert.ok(child.foo, 'child properties set');
-
-    superCalled = false;
-  });
-});
-
-QUnit.test('should have a super_ pointer', function(assert) {
-  assert.expect(4);
-
-  [function() {}, class Parent {}].forEach(Parent => {
-    const Child = extend(Parent, {
-      foo: 'bar'
-    });
-    const child = new Child();
-
-    assert.ok(child.foo, 'child properties set');
-    assert.equal(child.constructor.super_, Parent, 'super_ is present and equal to the super class');
-  });
-});
-
-QUnit.test('sub class is an ES6 class if the super class is', function(assert) {
-  class Parent {}
-
-  const Child = extend(Parent, {
-    foo: 'bar'
-  });
-
-  assert.ok(/^class/.test(Child.toString()), 'sub class is native es6 class');
-});