A function that finds the rectangle intersection of 2 rectangles

rectangleIntersection.js

const findRangeOverlap = (point1, length1, point2, length2) => {
  const highestStartPoint = Math.max(point1, point2);
  const lowestEndPoint = Math.min(point1 + length1, point2 + length2);
  
  if (highestStartPoint >= lowestEndPoint) {
    return {startPoint: null, width: null};
  }
  
  const overlapLength = lowestEndPoint - highestStartPoint;
  return {startPoint: highestStartPoint, overlapLength: overlapLength};
};


const getRectangleIntersection = (r1, r2) => {
  const x = findRangeOverlap(r1.leftx, r1.width, r2.leftx, r2.width);
  const y = findRangeOverlap(r1.bottomY, r1.height, r2.bottomY, r2.height);
  
  if (!x.overlapLength || !y.overlapLength) {
    return {
      leftx: null,
      bottomY: null,
      width: null,
      height: null
    };
  }
  
  return {
    leftx: x.startPoint,
    bottomY: y.startPoint,
    width: x.overlapLength,
    height: y.overlapLength
  };
};


// Example data
const rectangle1 = {
    leftx: 3,
    bottomY: 2,
    width: 5,
    height: 2
};

const rectangle2 = {
    leftx: 6,
    bottomY: 2,
    width: 2,
    height: 4
};

return getRectangleIntersection(rectangle1, rectangle2);