CODEWITHSUNDEEP
typescript
Vinod Pasi
Vinod Pasi

Reputation: 87

Equality Comparison

I am using TypeScript version Version 4.7.3. I am using the Equality Comparison with number and string.Below is the code

let a:number = 10;
let result = a=='10';

I am getting below compilation error.

This condition will always return 'false' since the types 'number' and 'string' have no overlap.ts(2367)

Upvotes: 0

Views: 1258

Answers (1)

kaya3
kaya3

Reputation: 51034

This is a known bug (see #26592); basically, == and === are treated the same for the purpose of this error message. To be clear, the bug is that the error message is wrong.

Typescript is supposed to be strongly-typed, so the use of type coercion is discouraged, even though it's valid in Javascript. If you want to compare a number and a string, then (from Typescript's perspective) instead of writing n == s, you should write String(n) === s or n === Number(s); or, make the two variables the same type in the first place.

So, a better error message would be something like "== operator on types number and string may be a mistake", although in my opinion, you just shouldn't use == at all.

Upvotes: 1

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