Remove .es6 from file extensions (!9241)

1 files changed, 158 insertions, 0 deletions

diff --git a/app/assets/javascripts/smart_interval.js b/app/assets/javascripts/smart_interval.js
new file mode 100644
index 00000000000..d1bdc353be2
--- /dev/null
+++ b/app/assets/javascripts/smart_interval.js
@@ -0,0 +1,158 @@
+/*
+* Instances of SmartInterval extend the functionality of `setInterval`, make it configurable
+* and controllable by a public API.
+*
+* */
+
+(() => {
+  class SmartInterval {
+    /**
+      * @param { function } opts.callback Function to be called on each iteration (required)
+      * @param { milliseconds } opts.startingInterval `currentInterval` is set to this initially
+      * @param { milliseconds } opts.maxInterval `currentInterval` will be incremented to this
+      * @param { milliseconds } opts.hiddenInterval `currentInterval` is set to this
+      *                         when the page is hidden
+      * @param { integer } opts.incrementByFactorOf `currentInterval` is incremented by this factor
+      * @param { boolean } opts.lazyStart Configure if timer is initialized on
+      *                    instantiation or lazily
+      * @param { boolean } opts.immediateExecution Configure if callback should
+      *                    be executed before the first interval.
+      */
+    constructor(opts = {}) {
+      this.cfg = {
+        callback: opts.callback,
+        startingInterval: opts.startingInterval,
+        maxInterval: opts.maxInterval,
+        hiddenInterval: opts.hiddenInterval,
+        incrementByFactorOf: opts.incrementByFactorOf,
+        lazyStart: opts.lazyStart,
+        immediateExecution: opts.immediateExecution,
+      };
+
+      this.state = {
+        intervalId: null,
+        currentInterval: this.cfg.startingInterval,
+        pageVisibility: 'visible',
+      };
+
+      this.initInterval();
+    }
+    /* public */
+
+    start() {
+      const cfg = this.cfg;
+      const state = this.state;
+
+      if (cfg.immediateExecution) {
+        cfg.immediateExecution = false;
+        cfg.callback();
+      }
+
+      state.intervalId = window.setInterval(() => {
+        cfg.callback();
+
+        if (this.getCurrentInterval() === cfg.maxInterval) {
+          return;
+        }
+
+        this.incrementInterval();
+        this.resume();
+      }, this.getCurrentInterval());
+    }
+
+    // cancel the existing timer, setting the currentInterval back to startingInterval
+    cancel() {
+      this.setCurrentInterval(this.cfg.startingInterval);
+      this.stopTimer();
+    }
+
+    onVisibilityHidden() {
+      if (this.cfg.hiddenInterval) {
+        this.setCurrentInterval(this.cfg.hiddenInterval);
+        this.resume();
+      } else {
+        this.cancel();
+      }
+    }
+
+    // start a timer, using the existing interval
+    resume() {
+      this.stopTimer(); // stop exsiting timer, in case timer was not previously stopped
+      this.start();
+    }
+
+    onVisibilityVisible() {
+      this.cancel();
+      this.start();
+    }
+
+    destroy() {
+      this.cancel();
+      document.removeEventListener('visibilitychange', this.handleVisibilityChange);
+      $(document).off('visibilitychange').off('beforeunload');
+    }
+
+    /* private */
+
+    initInterval() {
+      const cfg = this.cfg;
+
+      if (!cfg.lazyStart) {
+        this.start();
+      }
+
+      this.initVisibilityChangeHandling();
+      this.initPageUnloadHandling();
+    }
+
+    initVisibilityChangeHandling() {
+      // cancel interval when tab no longer shown (prevents cached pages from polling)
+      document.addEventListener('visibilitychange', this.handleVisibilityChange.bind(this));
+    }
+
+    initPageUnloadHandling() {
+      // TODO: Consider refactoring in light of turbolinks removal.
+      // prevent interval continuing after page change, when kept in cache by Turbolinks
+      $(document).on('beforeunload', () => this.cancel());
+    }
+
+    handleVisibilityChange(e) {
+      this.state.pageVisibility = e.target.visibilityState;
+      const intervalAction = this.isPageVisible() ?
+        this.onVisibilityVisible :
+        this.onVisibilityHidden;
+
+      intervalAction.apply(this);
+    }
+
+    getCurrentInterval() {
+      return this.state.currentInterval;
+    }
+
+    setCurrentInterval(newInterval) {
+      this.state.currentInterval = newInterval;
+    }
+
+    incrementInterval() {
+      const cfg = this.cfg;
+      const currentInterval = this.getCurrentInterval();
+      if (cfg.hiddenInterval && !this.isPageVisible()) return;
+      let nextInterval = currentInterval * cfg.incrementByFactorOf;
+
+      if (nextInterval > cfg.maxInterval) {
+        nextInterval = cfg.maxInterval;
+      }
+
+      this.setCurrentInterval(nextInterval);
+    }
+
+    isPageVisible() { return this.state.pageVisibility === 'visible'; }
+
+    stopTimer() {
+      const state = this.state;
+
+      state.intervalId = window.clearInterval(state.intervalId);
+    }
+  }
+  gl.SmartInterval = SmartInterval;
+})(window.gl || (window.gl = {}));