wrap() is wrong

[mikecann]

#489

import { describe, it, expect } from "@jest/globals";
import { wrap } from "./num";

describe("wrap", () => {
  it("works", () => {
    expect(wrap(11, 10, 25)).toEqual(11);
    expect(wrap(10, 10, 25)).toEqual(10);
    expect(wrap(9, 10, 25)).toEqual(25);
    expect(wrap(24, 10, 25)).toEqual(24);
    expect(wrap(25, 10, 25)).toEqual(25);
    expect(wrap(26, 10, 25)).toEqual(10);
  });
});

If you actually run these test you get different values from what is expected.

[mikecann]

This is what I came up with:

/**
 * Wraps a value between min and max, inclusive.
 *
 * e.g.
 *
 *     expect(wrap(0, 0, 9)).toEqual(0);
 *     expect(wrap(1, 0, 9)).toEqual(1);
 *     expect(wrap(9, 0, 9)).toEqual(9);
 *     expect(wrap(10, 0, 9)).toEqual(0);
 *     expect(wrap(11, 0, 9)).toEqual(1);
 *     expect(wrap(19, 0, 9)).toEqual(9);
 *     expect(wrap(10, 0, 9)).toEqual(0);
 *     expect(wrap(-1, 0, 9)).toEqual(9);
 *     expect(wrap(-10, 0, 9)).toEqual(0);
 *     expect(wrap(-11, 0, 9)).toEqual(9);
 *
 *     expect(wrap(10, 10, 19)).toEqual(10);
 *     expect(wrap(11, 10, 19)).toEqual(11);
 *     expect(wrap(19, 10, 19)).toEqual(19);
 *     expect(wrap(20, 10, 19)).toEqual(10);
 *
 * @param value
 * @param min the minimum inclusive value
 * @param max the maximum inclusive value
 */
export function wrap(value: number, min: number, max: number): number {
  const rangeSize = max - min + 1;
  if (value < min) return max - ((min - value - 1) % rangeSize);
  else return min + ((value - min) % rangeSize);
}