I'm getting a TS18047 on a comparison where the false result of null comparison is a desired outcome.

so, basically:

const a: number | null = null;
if (a >= 250) { /* will not execute because result of comparison is false */ }

this is what I want. and this code also worked before I introduced typescript.

I know I could just do a null check, but there's like ten branches comparing this variable against various numbers.

Only the final else processes the actual null value.

Do I actually have to check for null or is it possible for me to wiggle out of this?

CodePudding user response：

Well this should technically work because you can't compare something that's null to a number because it will always be false, so you need to null check it first.

if (a && a >= 250) {
      // do something

 }

This will also work but it's not best practice because it defeats the purpose of typescript

    if (a! >= 250) {
      // do something

 }

CodePudding user response：

The typeof Method has sometimes worked for me.

   if (typeof a == 'number' && a >= 250) {
        //do something 
}