Comparison between uninitialized arrays fail

[omarjackman]

Performing a deep equal on an uninitialized array doesn't behave as expected.

      const myTestArray1 = [undefined, 'test']
      const myTestArray2 = []
      // myTestArray2[0] should be equal to undefined by default
      myTestArray2[1] = 'test'

      expect(myTestArray1).to.deep.equal(myTestArray2)

I would expect these two arrays to pass a deep equality check since javascript seems to default uninitialized values to undefined

[omarjackman]

Just looking at chrome dev console it shows something called empty but I couldn't find any documentation on what that is but I'm guessing its related to this issue

[omarjackman]

workaround is to use

expect(lodashIsEqual(myTestArray1, myTestArray2)).to.be.true

[andrew1007]

The concept of an index being empty and undefined are two distinct concepts. undefined is considered an actual entry in specific index, but empty denotes nothing. JavaScript utilizes sparse arrays https://www.oreilly.com/library/view/javascript-the-definitive/9781449393854/ch07s03.html