[ES6] should.equal fails for Symbols

Hallo 😄

I ran into this small issue while testing Symbol equality using the should syntax:

let prince = Symbol("Love");

expect(prince).to.equal(prince);  // Passes
prince.should.equal(prince);  // AssertionError: expected {} to equal {}

Adding || this instanceof Symbol to the shouldGetter resolved the issue. I’m not sure if a PR is desired since it’s ES6-specific?

Thanks!

[meeber]

Sounds good 😄

I’ll submit a PR after work today if it’s still open then.

Edit: Working on this now.

[keithamus]

I guess the main question is: If a user does shadow an object’s valueOf with a function, is there any potential for an assertion to behave differently than before since this.valueOf() would now be passed in instead of this?

Yeah… you raise a good point here. This could be potentially dangerous for that exact reason actually. Probably best just to add the extra Symbol code there, as per your original comment. In fact we could handle it a bit easier by doing typeof this === 'symbol' - seeing as every browser that supports Symbols also supports typeof Symbol() === 'symbol'.

Regardless, probably good to add a pair of Symbol tests…

Absolutely.

I’ll mark this as PR wanted - based on the following criteria:

• The PR just adds the extra check for Symbols in the if - as described above
• The PR has tests to back up the correct behaviour for should
• Those tests should be conditional, so the tests still pass in browsers which don’t support Symbols.