Entity.js

class Entity {
  constructor(iterations) {
    this.dots = [];
    this.sticks = [];
    this.iterations = iterations || 16;
  }

  addDot(x, y, vx, vy) {
    this.dots.push(new Dot(x, y, vx, vy));
  }

  addStick(p1, p2, length) {
    this.sticks.push(new Stick(this.dots[p1], this.dots[p2], length));
  }

  updatePoints() {
    for (let i = 0; i < this.dots.length; i++) {
      this.dots[i].update();
    }
  }

  updateSticks() {
    for (let i = 0; i < this.sticks.length; i++) {
      this.sticks[i].update();
    }
  }

  updateContrains() {
    for (let i = 0; i < this.dots.length; i++) {
      this.dots[i].constrain();
    }
  }

  renderPoints(ctx) {
    for (let i = 0; i < this.dots.length; i++) {
      this.dots[i].render(ctx);
    }
  }
  renderSticks(ctx) {
    for (let i = 0; i < this.sticks.length; i++) {
      this.sticks[i].render(ctx);
    }
  }

  update(ctx) {

    this.updatePoints();
    for (let j = 0; j < this.iterations; j++) {
      this.updateSticks();
      this.updateContrains();
    }
    this.renderPoints(ctx);
    this.renderSticks(ctx);
  }
}