It should be noted that in the detail, m > 2.

Thank you for your attention.I also had this issue.

¡Vale la pena tanto código!
Ya tenemos defindo el tipo BigInt gracias a ti! ;-)

Fails on: gap(3, 3, 4), gap(2, 2, 6), gap(4, 6, 11), gap(4, 7, 11).

This fails with gap(2, 2, 6), should be null and returns [0,2].
Also @lindaxiao-hust said also fails with gap(3, 3, 4) should be null and returns [0,3]

Fails on gap(4, 6, 11) and gap(4, 7, 11) returns null on both and should be [7,11].

@ivanK_rep, Can you please explain me how to create a test for this kata? I don't know to create the "node" to test (I'm new to JavaScript since 1996!). Thank you!

I don't know what "spoiler" means, sorry!
Now I know, sorry again!

Please use spoiler flag next time.

Evidentemente desconocía Number.isInteger y mis matemáticas no son muy buenas ya que el bucle ese para encontrar el siguiente se reduce a:

// En realidad todo el código se reduce a esto:
let root = Math.sqrt(sq);
Number.isInteger(root) ? Math.pow(root + 1, 2) : -1;

Simple y claro, me ha ayudado a entender cómo funciona reduce (que desconocía)