Snippet: Method to update the diagonal velocity of a body

updateVelocity

/**
 * Updates the diagonal velocity properties of a body,
 * taking into account the body's current velocity 
 * and applying any forces acting against the body
 * as acceleration on both the x and y axis.
 * 
 * NOTE: This method DOES NOT update the position of 
 * the body, it only updates its velocity.
 * 
 * @param {Object} body: The body must be an Object 
 * with velocityX, velocityY and rotation properties. 
 * @param {Number} forceOnX: The force acting against
 * the body on the x axis.
 * @param {Number} forceOnY: The force acting against
 * the body on the y axis.
 */
updateVelocity(body, forceOnX, forceOnY) {
  const
    angle = body.rotation * Math.PI / 180,
    accelerationOnX  = Math.cos(angle) * forceOnX,
    accelerationOnY = Math.sin(angle) * forceOnY;
  body.velocityX += accelerationOnX;
  body.velocityY += accelerationOnY;
},