Chapter 4 Exercise 5

[TheGhostHuCodes]

Thanks for writing this great book. I'm new to TypeScript and I'm enjoying working through it.

I noticed that the answer to Chapter 4 Exercise 5 has the function signature:

function is<T>(a: T, ...b: [T, ...T[]]): boolean

However, when I was attempting it on my own, I came up with:

function is<T>(a: T, ...b: T[]): boolean

which also seems to work. It looks like there's also an open PR (#8) with the signature:

function is<T>(a: T, ...b: [...T[]]): boolean

What's the difference, if any, between these different generic types?

[tmnvanderberg]

I came here to ask the same question.

[tmnvanderberg]

Just noticed the question was answer on the PR. The reason is to avoid users calling is('a') with a single argument.