AnimatedLineString

AnimatedLineString2.js

export class AnimatedLineString2 extends AnimatedWithChildren {
  constructor(line) {
    super();

    this.coordinates = line.coordinates.map(coord => [...coord]);
  }

  // eslint-disable-next-line class-methods-use-this
  _onAnimationDone(animation, doneCB) {
    return new Proxy(animation, {
      get(obj, prop) {
        if (prop === 'start') {
          return function start(origDoneCB, ...args) {
            return obj.start((startParams, ...startArgs) => {
              doneCB(startParams);
              if (origDoneCB) {
                origDoneCB(startParams, ...startArgs);
              }
            }, ...args);
          };
        }
        return obj[prop];
      },
    });
  }

  _last(items) {
    return items.length > 0 ? items[items.length - 1] : null;
  }

  _setup(coordinates) {
    const last = this._last(this.coordinates);

    let i = this.coordinates.length;

    while (i < coordinates.length) {
      this.coordinates.push([...last]);
      i++;
    }
  }

  _cleanup(coordinates) {
    while (this.coordinates.length > coordinates.length) {
      this.coordinates.pop();
    }
    super.__callListeners(this.__getValue());
  }

  animate(type, config) {
    const {coordinates, ...rest} = config;
    const last = this._last(coordinates);

    this._setup(coordinates);

    this.value = new Animated.Value(0.0);
    this.newCoords = coordinates.map(coord => [...coord]);
    this.animation = Animated[type](this.value, {...rest, toValue: 1.0});
    this.value.__addChild(this);
    return this.animation;
  }

  timing(config = {coordinates: DEFAULT_COORD}) {
    return this.animate('timing', config);
  }

  __getValue() {
    if (!this.animation) {
      return {
        type: 'LineString',
        coordinates: this.coordinates.map(coord => [coord[0], coord[1]]),
      };
    }
    const newF = this.value.__getValue();
    const origF = 1.0 - newF;
    return {
      type: 'LineString',
      coordinates: this.coordinates.map((coord, i) => {
        if (this.newCoords.length > i) {
          const newCoord = this.newCoords[i];
          return [
            coord[0] * origF + newCoord[0] * newF,
            coord[1] * origF + newCoord[1] * newF,
          ];
        }
        return [coord[0], coord[1]];
      }),
    };
  }
}