private updateSnapPosition()

in client/src/components/translation-selector/word-scroll-list.ts [380:423]
41 lines of code
13 McCabe index (conditional complexity)

  private updateSnapPosition(lastProperties: {position: number, velocity: number, time: number}, snapWordIndex: number) {
    let velocity = lastProperties.velocity;
    if(lastProperties.position < this.minScrollPosition && velocity < 0) {
      velocity = 0;
    } else if(lastProperties.position > 0 && velocity > 0) {
      velocity = 0;
    } else if (Math.abs(velocity) > this.config.snapMaxSpeed) {
      velocity = Math.sign(velocity) * this.config.snapMaxSpeed;
    }
    const snapPosition = this.getWordSnapPosition(snapWordIndex);
    const t = WordScrollListComponent.getTime();
    const dt = t - lastProperties.time;
    const snapDx = snapPosition - lastProperties.position;
    velocity += snapDx < 0 ? - this.config.snapAcceleration * dt : this.config.snapAcceleration * dt;
    let maxSpeed = this.config.snapMaxSpeed;
    if (Math.abs(snapDx) <= this.config.snapDecelerationDistance) {
      // near snap position - start slowing down
      maxSpeed *= Math.abs(snapDx) / this.config.snapDecelerationDistance;
    }
    if (Math.abs(velocity) > maxSpeed) {
      // over max speed
      velocity = Math.sign(velocity) * maxSpeed;
    }
    if (Math.abs(velocity) < this.config.snapMinSpeed) {
      // under min speed
      velocity = Math.sign(velocity) * this.config.snapMinSpeed;
    }
    const dx = 0.5 * (velocity + lastProperties.velocity) * dt;
    if (Math.sign(dx) === Math.sign(snapDx) && Math.abs(dx) >= Math.abs(snapDx) && Math.abs(dx) < 10) {
      // close enough - end snap
      this.setScrollPosition(snapPosition);
      clearInterval(this.snapInterval);
      this.snapInterval = null;
      this.selectedWordIndex = this.getWordIndexFromScrollPosition(snapPosition);
    } else {
      const position = lastProperties.position + dx;
      this.setScrollPosition(position);
      lastProperties.velocity = velocity;
      lastProperties.position = position;
      lastProperties.time = t;
      this.selectedWordIndex = this.getWordIndexFromScrollPosition(position);
    }
    this.updateTargetPosition();
  }