1 files changed, 70 insertions, 0 deletions
diff --git a/devtools/client/inspector/animation/utils/utils.js b/devtools/client/inspector/animation/utils/utils.js
new file mode 100644
index 0000000000..9040c27213
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+++ b/devtools/client/inspector/animation/utils/utils.js
@@ -0,0 +1,70 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// The maximum number of times we can loop before we find the optimal time interval in the
+// timeline graph.
+const OPTIMAL_TIME_INTERVAL_MAX_ITERS = 100;
+// Time graduations should be multiple of one of these number.
+const OPTIMAL_TIME_INTERVAL_MULTIPLES = [1, 2.5, 5];
+
+/**
+ * Find the optimal interval between time graduations in the animation timeline
+ * graph based on a minimum time interval.
+ *
+ * @param {Number} minTimeInterval
+ *                 Minimum time in ms in one interval
+ * @return {Number} The optimal interval time in ms
+ */
+function findOptimalTimeInterval(minTimeInterval) {
+  if (!minTimeInterval) {
+    return 0;
+  }
+
+  let numIters = 0;
+  let multiplier = 1;
+  let interval;
+
+  while (true) {
+    for (let i = 0; i < OPTIMAL_TIME_INTERVAL_MULTIPLES.length; i++) {
+      interval = OPTIMAL_TIME_INTERVAL_MULTIPLES[i] * multiplier;
+
+      if (minTimeInterval <= interval) {
+        return interval;
+      }
+    }
+
+    if (++numIters > OPTIMAL_TIME_INTERVAL_MAX_ITERS) {
+      return interval;
+    }
+
+    multiplier *= 10;
+  }
+}
+
+/**
+ * Check whether or not the given list of animations has an iteration count of infinite.
+ *
+ * @param {Array} animations.
+ * @return {Boolean} true if there is an animation in the  list of animations
+ *                   whose animation iteration count is infinite.
+ */
+function hasAnimationIterationCountInfinite(animations) {
+  return animations.some(({ state }) => !state.iterationCount);
+}
+
+/**
+ * Check wether the animations are running at least one.
+ *
+ * @param {Array} animations.
+ * @return {Boolean} true: running
+ */
+function hasRunningAnimation(animations) {
+  return animations.some(({ state }) => state.playState === "running");
+}
+
+exports.findOptimalTimeInterval = findOptimalTimeInterval;
+exports.hasAnimationIterationCountInfinite = hasAnimationIterationCountInfinite;
+exports.hasRunningAnimation = hasRunningAnimation;