success/packages/excalidraw/math.test.ts

import { rangeIntersection, rangesOverlap, rotate } from "./math";

describe("rotate", () => {
  it("should rotate over (x2, y2) and return the rotated coordinates for (x1, y1)", () => {
    const x1 = 10;
    const y1 = 20;
    const x2 = 20;
    const y2 = 30;
    const angle = Math.PI / 2;
    const [rotatedX, rotatedY] = rotate(x1, y1, x2, y2, angle);
    expect([rotatedX, rotatedY]).toEqual([30, 20]);
    const res2 = rotate(rotatedX, rotatedY, x2, y2, -angle);
    expect(res2).toEqual([x1, x2]);
  });
});

describe("range overlap", () => {
  it("should overlap when range a contains range b", () => {
    expect(rangesOverlap([1, 4], [2, 3])).toBe(true);
    expect(rangesOverlap([1, 4], [1, 4])).toBe(true);
    expect(rangesOverlap([1, 4], [1, 3])).toBe(true);
    expect(rangesOverlap([1, 4], [2, 4])).toBe(true);
  });

  it("should overlap when range b contains range a", () => {
    expect(rangesOverlap([2, 3], [1, 4])).toBe(true);
    expect(rangesOverlap([1, 3], [1, 4])).toBe(true);
    expect(rangesOverlap([2, 4], [1, 4])).toBe(true);
  });

  it("should overlap when range a and b intersect", () => {
    expect(rangesOverlap([1, 4], [2, 5])).toBe(true);
  });
});

describe("range intersection", () => {
  it("should intersect completely with itself", () => {
    expect(rangeIntersection([1, 4], [1, 4])).toEqual([1, 4]);
  });

  it("should intersect irrespective of order", () => {
    expect(rangeIntersection([1, 4], [2, 3])).toEqual([2, 3]);
    expect(rangeIntersection([2, 3], [1, 4])).toEqual([2, 3]);
    expect(rangeIntersection([1, 4], [3, 5])).toEqual([3, 4]);
    expect(rangeIntersection([3, 5], [1, 4])).toEqual([3, 4]);
  });

  it("should intersect at the edge", () => {
    expect(rangeIntersection([1, 4], [4, 5])).toEqual([4, 4]);
  });

  it("should not intersect", () => {
    expect(rangeIntersection([1, 4], [5, 7])).toEqual(null);
  });
});