[prefer-reduce-type-parameter] fix results in invalid code #3584
Description
- I have tried restarting my IDE and the issue persists.
- I have updated to the latest version of the packages.
- I have read the FAQ and my problem is not listed.
Repro
{
"rules": {
"@typescript-eslint/prefer-reduce-type-parameter": 2
}
}declare const arr1: string[];
declare const arr2: string[];
const text = arr1.reduce<string>((acc) => acc, arr1.shift() as string);{
"compilerOptions": {
"target": "es6",
"module": "commonjs",
"allowJs": true,
"declaration": true,
"strict": true,
"noImplicitAny": false,
"moduleResolution": "node",
"esModuleInterop": true,
"preserveSymlinks": true,
"resolveJsonModule": true
},
"exclude": ["**/*.spec.ts", "**/*.spec.tsx", "**/__tests__", "**/dist/**/*"],
"include": ["src/**/*", "index.ts"]
}Expected Result
One of three options.
Either don't report this as an error, since the default value's type is string | undefined, and setting the reduce's type parameter as string leads to a TS error.
declare const arr1: string[];
declare const arr2: string[];
const text = arr1.reduce<string>((acc) => acc, arr1.shift() as string);Or remove the type parameter from the reduce, and leave the one at the typecasting.
declare const arr1: string[];
declare const arr2: string[];
const text = arr1.reduce((acc) => acc, arr1.shift() as string);Or, finally, remove the casting without breaking the code
declare const arr1: string[];
declare const arr2: string[];
const text = arr1.reduce<string>((acc) => acc, arr1.shift());Actual Result
The fix turns the code into the following
declare const arr1: string[];
declare const arr2: string[];
const text = arr1.reduce<string><string>((acc) => acc, arr1.shift());Additional Info
Versions
| package | version |
|---|---|
@typescript-eslint/eslint-plugin |
4.28.0 |
@typescript-eslint/parser |
4.28.0 |
TypeScript |
4.3.3 |
ESLint |
7.29.0 |
node |
14.15.5 |