animated/src/AnimatedTracking.js

Declarative Animations Library for React and React Native

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @flow
 */
'use strict';

var Animated = require('./Animated');
var AnimatedValue = require('./AnimatedValue');

import type { EndCallback } from './Animated';

class AnimatedTracking extends Animated {
  _value: AnimatedValue;
  _parent: Animated;
  _callback: ?EndCallback;
  _animationConfig: Object;
  _animationClass: any;

  constructor(
    value: AnimatedValue,
    parent: Animated,
    animationClass: any,
    animationConfig: Object,
    callback?: ?EndCallback,
  ) {
    super();
    this._value = value;
    this._parent = parent;
    this._animationClass = animationClass;
    this._animationConfig = animationConfig;
    this._callback = callback;
    this.__attach();
  }

  __getValue(): Object {
    return this._parent.__getValue();
  }

  __attach(): void {
    this._parent.__addChild(this);
  }

  __detach(): void {
    this._parent.__removeChild(this);
  }

  update(): void {
    this._value.animate(new this._animationClass({
      ...this._animationConfig,
      toValue: (this._animationConfig.toValue: any).__getValue(),
    }), this._callback);
  }
}

module.exports = AnimatedTracking;