TypeScript: exclude "null" and "undefined" from a value of type

Question

Support there is some value:

let value: string | null;

then somewhere along the way I'm certain that it's never null. But there is a function that expects a non-nullable type:

function my_func(arg: string){}

How do I tell TypeScript that my value is alright for it?

my_func(value);
// Argument of type 'string | null' is not assignable 
// to parameter of type 'string'

I know it's a noob question and it has an answer elsewhere, but that question is not google-friendly for people looking to solve a specific problem. This one is. — kolypto, Sep 25 '21 at 23:37

score 1 · Accepted Answer · answered Sep 25 '21 at 23:34

1

Simply use !:

my_func(value!);

answered Sep 25 '21 at 23:34

kolypto

1 Answers1