Repository: chartjs/Chart.js
File: test/specs/helpers.collection.tests.js (JavaScript)

Code before:
  it('Should do binary search', function() {
    const data = [0, 2, 6, 9];
    expect(_lookup(data, 0)).toEqual({lo: 0, hi: 1});
    expect(_lookup(data, 1)).toEqual({lo: 0, hi: 1});
    expect(_lookup(data, 3)).toEqual({lo: 1, hi: 2});
    expect(_lookup(data, 6)).toEqual({lo: 1, hi: 2});
    expect(_lookup(data, 9)).toEqual({lo: 2, hi: 3});
  });

  it('Should do binary search by key', function() {
    const data = [{x: 0}, {x: 2}, {x: 6}, {x: 9}];
    expect(_lookupByKey(data, 'x', 0)).toEqual({lo: 0, hi: 1});
    expect(_lookupByKey(data, 'x', 1)).toEqual({lo: 0, hi: 1});
    expect(_lookupByKey(data, 'x', 3)).toEqual({lo: 1, hi: 2});
    expect(_lookupByKey(data, 'x', 6)).toEqual({lo: 1, hi: 2});
    expect(_lookupByKey(data, 'x', 9)).toEqual({lo: 2, hi: 3});
  });

  it('Should do reverse binary search by key', function() {
    const data = [{x: 10}, {x: 7}, {x: 3}, {x: 0}];
    expect(_rlookupByKey(data, 'x', 0)).toEqual({lo: 2, hi: 3});
    expect(_rlookupByKey(data, 'x', 3)).toEqual({lo: 2, hi: 3});
    expect(_rlookupByKey(data, 'x', 5)).toEqual({lo: 1, hi: 2});
    expect(_rlookupByKey(data, 'x', 8)).toEqual({lo: 0, hi: 1});
    expect(_rlookupByKey(data, 'x', 10)).toEqual({lo: 0, hi: 1});
  });

  it('Should filter a sorted array', function() {
    expect(_filterBetween([1, 2, 3, 4, 5, 6, 7, 8, 9], 5, 8)).toEqual([5, 6, 7, 8]);
    expect(_filterBetween([1], 1, 1)).toEqual([1]);
    expect(_filterBetween([1583049600000], 1584816327553, 1585680327553)).toEqual([]);
  });
});


Review comment (suggestion):
Just for discussion, wouldn't it be better if it returned lo:2, hi:4 in this case? (Thus including the whole range with same x)

Code after:
  it('Should do binary search', function() {
    const data = [0, 2, 6, 9];
    expect(_lookup(data, 0)).toEqual({lo: 0, hi: 1});
    expect(_lookup(data, 1)).toEqual({lo: 0, hi: 1});
    expect(_lookup(data, 3)).toEqual({lo: 1, hi: 2});
    expect(_lookup(data, 6)).toEqual({lo: 1, hi: 2});
    expect(_lookup(data, 9)).toEqual({lo: 2, hi: 3});
  });

  it('Should do binary search by key', function() {
    const data = [{x: 0}, {x: 2}, {x: 6}, {x: 9}];
    expect(_lookupByKey(data, 'x', 0)).toEqual({lo: 0, hi: 1});
    expect(_lookupByKey(data, 'x', 1)).toEqual({lo: 0, hi: 1});
    expect(_lookupByKey(data, 'x', 3)).toEqual({lo: 1, hi: 2});
    expect(_lookupByKey(data, 'x', 6)).toEqual({lo: 1, hi: 2});
    expect(_lookupByKey(data, 'x', 9)).toEqual({lo: 2, hi: 3});
  });

  it('Should do binary search by key with last', () => {
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 6}, {x: 9}], 'x', 25, true)).toEqual({lo: 2, hi: 3});
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 9}, {x: 9}], 'x', 25, true)).toEqual({lo: 2, hi: 3});
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 9}, {x: 9}, {x: 22}], 'x', 25, true)).toEqual({lo: 3, hi: 4});
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 25}, {x: 28}], 'x', 25, true)).toEqual({lo: 1, hi: 2});
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 25}, {x: 25}], 'x', 25, true)).toEqual({lo: 2, hi: 3});
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 25}, {x: 25}, {x: 28}], 'x', 25, true)).toEqual({lo: 2, hi: 3});
    expect(_lookupByKey([{x: 0}, {x: 2}, {x: 25}, {x: 25}, {x: 25}, {x: 28}, {x: 29}], 'x', 25, true)).toEqual({lo: 3, hi: 4});
  });

  it('Should do reverse binary search by key', function() {
    const data = [{x: 10}, {x: 7}, {x: 3}, {x: 0}];
    expect(_rlookupByKey(data, 'x', 0)).toEqual({lo: 2, hi: 3});
    expect(_rlookupByKey(data, 'x', 3)).toEqual({lo: 2, hi: 3});
    expect(_rlookupByKey(data, 'x', 5)).toEqual({lo: 1, hi: 2});
    expect(_rlookupByKey(data, 'x', 8)).toEqual({lo: 0, hi: 1});
    expect(_rlookupByKey(data, 'x', 10)).toEqual({lo: 0, hi: 1});
  });

  it('Should filter a sorted array', function() {
    expect(_filterBetween([1, 2, 3, 4, 5, 6, 7, 8, 9], 5, 8)).toEqual([5, 6, 7, 8]);
    expect(_filterBetween([1], 1, 1)).toEqual([1]);
    expect(_filterBetween([1583049600000], 1584816327553, 1585680327553)).toEqual([]);
  });
});