TS2367

Comparison with no overlap

This comparison appears to be unintentional because the types 'string' and 'number' have no overlap.

The compiler’s own words. Not translated — this is the string you pasted into a search box.

The two sides can never be equal, so the comparison is always false and the compiler assumes you did not mean to write it.

Reproduction

declare const a: string

if (a === 1) {
}

The build asserts this emits exactly this code.

Why the compiler says this

This is one of the few diagnostics that is about intent rather than safety — the comparison would run perfectly well and return `false` forever. It fires most usefully after a refactor, when a variable that used to be a union has been narrowed and a branch that once mattered has quietly become dead code. Treat it as a note that something upstream changed.

Fixes

declare const a: string

if (a === '1') {
}

Compare against the type you actually have.

02
```
declare const a: string | number

if (a === 1) {
}
```
Or widen the variable, if it really can be either. Then the comparison has a purpose again and narrows `a` to `number` inside the block.

Takeaway

A comparison the compiler calls pointless is usually a branch that used to be reachable. Delete it or fix the type it was guarding — do not cast to keep it.

Where to go next

Conditional types Try it in the Lab

Errors