Suspicious handling of a number (result of area) as a boolean

[OndrejSpanel]

Is handling the number result of the area call as a boolean value intended in the snippet below?

https://github.com/mapbox/earcut/blob/36742a5a24497f56d89f024a7b44a0a4f8e07128/src/earcut.js#L476-L481

As I understand the code now, it checks that at least one of the triangles a.prev, a, b.prev and a, b.prev, b has non zero area. I do not understand the intent well enough, the comment says "does not create opposite-facing sectors".

If the code is correct, perhaps an explicit comparion using !== 0 would make the intent clearer?

(Originally reported as https://github.com/mrdoob/three.js/issues/20200)