sindresorhus/eslint-plugin-unicorn
Rule proposal: `no-unused-return-value`
Closed
#741 opened on May 22, 2020
help wantednew rule
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Description
Details here: https://github.com/eslint/eslint/issues/12980
The idea is that many builtin functions return values and if those return values are not used, the code is essentially a noop and can be removed.
The discussion got stale because it seems hard for a plugin to correctly judge the type of a variable which is essential for a rule like this so it may require Typescript to really be useful. Also there was the problem of getters which would trigger false positives but I generally see getters as a obscure feature that should not be used.
Fail
const arr = [{name: 'eslint'}];
arr.map(item => item.name); // error: Unused Array.prototype.map return value
console.log(arr);
Pass
const arr = [{name: 'eslint'}];
console.log(arr);
Fail
let i = 0;
const arr = [1,2,3];
arr.map((item) => { // error: Unused Array.prototype.map return value
i += 1;
});
Pass
let i = 0;
const arr = [1,2,3];
arr.forEach((item) => {
i += 1;
});