toCommonUnit doesn't work as expected

[gvlasov]

Why does this fail?

  it("should convert measurements to a common unit", () => {
    expect(toCommonUnit([1, 'cm'], [2, 'm'])).not.toBeUndefined()
  });

I would expect it to return [[1, 'cm'], [200, 'cm']], but it returns undefined.

[gvlasov]

Reading this test I can see that this function doesn't do what I expected it to do.

How do you bring two measurements of the same dimension to the same unit?

[gvlasov]

Or how do you compare two measurements of the same dimension with different units? That would solve my problem as well.