What version of Oxlint are you using?
1.51.0, oxlint-tsgolint 0.16.0
What command did you run?
oxlint
What does your .oxlintrc.json (or oxlint.config.ts) config file look like?
What happened?
@typescript-eslint/no-unnecessary-condition reports a false positive on ?. after a call to an overloaded method when the argument type is T | undefined.
The method has two overloads:
valueOf(entry: string): MyEnum (non-nullable return)valueOf(entry: string | undefined): MyEnum | undefined (nullable return)
When called with an string | undefined argument, TypeScript correctly selects the second overload, returning MyEnum | undefined. The ?. is therefore necessary. oxlint appears to resolve to the first overload instead and considers the value non-nullish.
tsconfig.json:
{
"compilerOptions": {
"module": "ESNext",
"target": "ES2023",
"moduleResolution": "bundler",
"strict": true,
"noEmit": true,
"skipLibCheck": true
},
"include": ["src"]
} src/example.ts:
class MyEnum {
public readonly readableName: string;
private constructor(readableName: string) {
this.readableName = readableName;
}
public static readonly A = new MyEnum('Type A');
public static readonly B = new MyEnum('Type B');
public static valueOf(entry: string): MyEnum;
public static valueOf(entry: string | undefined): MyEnum | undefined;
public static valueOf(entry: string | undefined): MyEnum | undefined {
if (entry === 'A') {
return MyEnum.A;
}
if (entry === 'B') {
return MyEnum.B;
}
return undefined;
}
}
type Event = {
type?: string;
};
export function getReadableName(event: Event): string {
return MyEnum.valueOf(event.type)?.readableName ?? 'unknown';
}
export { MyEnum, getReadableName }; Reported diagnostic:
x typescript-eslint(no-unnecessary-condition): Unnecessary optional chain on a non-nullish value.
,-[src/example.ts:30:9]
29 | function getReadableName(event: Event): string {
30 | return MyEnum.valueOf(event.type)?.readableName ?? 'unknown';
: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
31 | }
`----
What version of Oxlint are you using?
1.51.0, oxlint-tsgolint 0.16.0
What command did you run?
oxlint
What does your
.oxlintrc.json(oroxlint.config.ts) config file look like?{ "plugins": ["typescript"], "options": { "typeAware": true }, "rules": { "@typescript-eslint/no-unnecessary-condition": "error" } }What happened?
@typescript-eslint/no-unnecessary-conditionreports a false positive on?.after a call to an overloaded method when the argument type isT | undefined.The method has two overloads:
valueOf(entry: string): MyEnum(non-nullable return)valueOf(entry: string | undefined): MyEnum | undefined(nullable return)When called with an
string | undefinedargument, TypeScript correctly selects the second overload, returningMyEnum | undefined. The?.is therefore necessary. oxlint appears to resolve to the first overload instead and considers the value non-nullish.tsconfig.json:
{ "compilerOptions": { "module": "ESNext", "target": "ES2023", "moduleResolution": "bundler", "strict": true, "noEmit": true, "skipLibCheck": true }, "include": ["src"] }src/example.ts:
Reported diagnostic: