raf-stub/dist/raf-stub.js

Accurate and predictable testing of requestAnimationFrame and cancelAnimationFrame

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (global = global || self, factory(global.rafStub = {}));
}(this, function (exports) { 'use strict';

  var defaultFrameDuration = 1000 / 60;

  var now = (function () {
    if (performance) {
      return performance.now();
    }

    return Date.now();
  });

  function createStub(frameDuration, startTime) {
    if (frameDuration === void 0) {
      frameDuration = defaultFrameDuration;
    }

    if (startTime === void 0) {
      startTime = now();
    }

    var frames = [];
    var frameId = 0;
    var currentTime = startTime;

    var add = function add(cb) {
      var id = ++frameId;

      var callback = function callback(time) {
        cb(time);
        remove(id);
      };

      frames.push({
        id: id,
        callback: callback
      });
      return id;
    };

    var remove = function remove(id) {
      var index = frames.findIndex(function (frame) {
        return frame.id === id;
      });

      if (index === -1) {
        return;
      }

      frames.splice(index, 1);
    };

    var flush = function flush(duration) {
      if (duration === void 0) {
        duration = frameDuration;
      }

      while (frames.length) {
        step(1, duration);
      }
    };

    var reset = function reset() {
      frames.length = 0;
      currentTime = startTime;
    };

    var step = function step(steps, duration) {
      if (steps === void 0) {
        steps = 1;
      }

      if (duration === void 0) {
        duration = frameDuration;
      }

      if (steps === 0) {
        return;
      }

      currentTime = currentTime + duration;
      var shallow = frames.slice(0);
      shallow.forEach(function (frame) {
        frame.callback(currentTime);
      });
      return step(steps - 1, duration);
    };

    var api = {
      add: add,
      remove: remove,
      reset: reset,
      flush: flush,
      step: step
    };
    return api;
  }
  function replaceRaf(roots, _temp) {
    if (roots === void 0) {
      roots = [];
    }

    var _ref = _temp === void 0 ? {} : _temp,
        _ref$frameDuration = _ref.frameDuration,
        frameDuration = _ref$frameDuration === void 0 ? defaultFrameDuration : _ref$frameDuration,
        _ref$startTime = _ref.startTime,
        startTime = _ref$startTime === void 0 ? now() : _ref$startTime;

    if (!roots.length) {
      roots.push(typeof window !== 'undefined' ? window : global);
    }

    var stub = createStub(frameDuration, startTime);
    roots.forEach(function (root) {
      root.requestAnimationFrame = stub.add;
      Object.assign(root.requestAnimationFrame, {
        step: stub.step,
        flush: stub.flush,
        reset: stub.reset
      });
      root.cancelAnimationFrame = stub.remove;
    });
  }

  exports.default = createStub;
  exports.replaceRaf = replaceRaf;

  Object.defineProperty(exports, '__esModule', { value: true });

}));