feat: Add a version class to the player (#4335)

Adds `vjs-v5` class so you can target that version of Video.js.

Author: mister-ben

src/js/player.js

@@ -413,6 +413,11 @@ class Player extends Component {
     // Make player easily findable by ID
     Player.players[this.id_] = this;
 
+    // Add a major version class to aid css in plugins
+    const majorVersion = require('../../package.json').version.split('.')[0];
+
+    this.addClass(`vjs-v${majorVersion}`);
+
     // When the player is first initialized, trigger activity so components
     // like the control bar show themselves if needed
     this.userActive(true);

test/unit/player.test.js

@@ -1387,3 +1387,12 @@ QUnit.test('should not allow to register custom player when any player has been
   // reset the Player to the original value;
   videojs.registerComponent('Player', Player);
 });
+
+QUnit.test('should add a class with major version', function(assert) {
+  const majorVersion = require('../../package.json').version.split('.')[0];
+  const player = TestHelpers.makePlayer();
+
+  assert.ok(player.hasClass('vjs-v' + majorVersion), 'the version class should be added to the player');
+
+  player.dispose();
+});