What is "not assignable to parameter of type never" error in typescript?

Question

Code is:

const foo = (foo: string) => {   const result = []   result.push(foo) } 

I get the following TS error:

[ts] Argument of type 'string' is not assignable to parameter of type 'never'.

What am I doing wrong? Is this a bug?

Answer 1

All you have to do is define your result as a string array, like the following:

const result : string[] = []; 

Without defining the array type, it by default will be never. So when you tried to add a string to it, it was a type mismatch, and so it threw the error you saw.

Answer 2

Another way is :

const result = [] as  any;