no-unused-map-result

Disallow unused Array.map and Iterator.map results

Discarding an Array map wastes its allocated result, while discarding an Iterator map leaves its lazy callback unconsumed.
Instead, you SHOULD call forEach when the callback work is intended or remove the unused map operation.

- Category: suspicious
- Level: warning
- Fix: suggestion
- Scope: module

Reported

function append(values: int32[], output: int32[]): void {
    values.map((value) => output.push(value));
}
Accepted

function append(values: int32[], output: int32[]): void {
    values.forEach((value) => output.push(value));
}
Prior art

- eslint-plugin-sonarjs · no-ignored-return

language/linter/src/rules/suspicious/nounusedmapresult.rs:8