Merge branch 'develop' into css-variables

# Conflicts:
#	demo/dist/demo.css
#	demo/dist/demo.js
#	demo/dist/demo.js.map
#	demo/dist/demo.min.js
#	demo/dist/demo.min.js.map
#	dist/plyr.css
#	dist/plyr.js
#	dist/plyr.js.map
#	dist/plyr.min.js
#	dist/plyr.min.js.map
#	dist/plyr.polyfilled.js
#	dist/plyr.polyfilled.js.map
#	dist/plyr.polyfilled.min.js
#	dist/plyr.polyfilled.min.js.map
#	gulpfile.js
#	src/sass/components/captions.scss
#	src/sass/components/control.scss

1 files changed, 120 insertions, 0 deletions

diff --git a/src/js/utils/events.js b/src/js/utils/events.js
new file mode 100644
index 00000000..9f734f04
--- /dev/null
+++ b/src/js/utils/events.js
@@ -0,0 +1,120 @@
+// ==========================================================================
+// Event utils
+// ==========================================================================
+
+import is from './is';
+
+// Check for passive event listener support
+// https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md
+// https://www.youtube.com/watch?v=NPM6172J22g
+const supportsPassiveListeners = (() => {
+    // Test via a getter in the options object to see if the passive property is accessed
+    let supported = false;
+    try {
+        const options = Object.defineProperty({}, 'passive', {
+            get() {
+                supported = true;
+                return null;
+            },
+        });
+        window.addEventListener('test', null, options);
+        window.removeEventListener('test', null, options);
+    } catch (e) {
+        // Do nothing
+    }
+
+    return supported;
+})();
+
+// Toggle event listener
+export function toggleListener(element, event, callback, toggle = false, passive = true, capture = false) {
+    // Bail if no element, event, or callback
+    if (!element || !('addEventListener' in element) || is.empty(event) || !is.function(callback)) {
+        return;
+    }
+
+    // Allow multiple events
+    const events = event.split(' ');
+
+    // Build options
+    // Default to just the capture boolean for browsers with no passive listener support
+    let options = capture;
+
+    // If passive events listeners are supported
+    if (supportsPassiveListeners) {
+        options = {
+            // Whether the listener can be passive (i.e. default never prevented)
+            passive,
+            // Whether the listener is a capturing listener or not
+            capture,
+        };
+    }
+
+    // If a single node is passed, bind the event listener
+    events.forEach(type => {
+        if (this && this.eventListeners && toggle) {
+            // Cache event listener
+            this.eventListeners.push({ element, type, callback, options });
+        }
+
+        element[toggle ? 'addEventListener' : 'removeEventListener'](type, callback, options);
+    });
+}
+
+// Bind event handler
+export function on(element, events = '', callback, passive = true, capture = false) {
+    toggleListener.call(this, element, events, callback, true, passive, capture);
+}
+
+// Unbind event handler
+export function off(element, events = '', callback, passive = true, capture = false) {
+    toggleListener.call(this, element, events, callback, false, passive, capture);
+}
+
+// Bind once-only event handler
+export function once(element, events = '', callback, passive = true, capture = false) {
+    function onceCallback(...args) {
+        off(element, events, onceCallback, passive, capture);
+        callback.apply(this, args);
+    }
+
+    toggleListener.call(this, element, events, onceCallback, true, passive, capture);
+}
+
+// Trigger event
+export function triggerEvent(element, type = '', bubbles = false, detail = {}) {
+    // Bail if no element
+    if (!is.element(element) || is.empty(type)) {
+        return;
+    }
+
+    // Create and dispatch the event
+    const event = new CustomEvent(type, {
+        bubbles,
+        detail: Object.assign({}, detail, {
+            plyr: this,
+        }),
+    });
+
+    // Dispatch the event
+    element.dispatchEvent(event);
+}
+
+// Unbind all cached event listeners
+export function unbindListeners() {
+    if (this && this.eventListeners) {
+        this.eventListeners.forEach(item => {
+            const { element, type, callback, options } = item;
+            element.removeEventListener(type, callback, options);
+        });
+
+        this.eventListeners = [];
+    }
+}
+
+// Run method when / if player is ready
+export function ready() {
+    return new Promise(
+        resolve => (this.ready ? setTimeout(resolve, 0) : on.call(this, this.elements.container, 'ready', resolve)),
+    ).then(() => {});
+}