no-empty-interface
Disallow the declaration of empty interfaces.
Some problems reported by this rule are automatically fixable by the --fix ESLint command line option.
Some problems reported by this rule are manually fixable by editor suggestions.
This rule has been deprecated in favour of the more comprehensive @typescript-eslint/no-empty-object-type rule.
An empty interface in TypeScript does very little: any non-nullable value is assignable to {}.
Using an empty interface is often a sign of programmer error, such as misunderstanding the concept of {} or forgetting to fill in fields.
This rule aims to ensure that only meaningful interfaces are declared in the code.
module.exports = {
"rules": {
"@typescript-eslint/no-empty-interface": "error"
}
};
Try this rule in the playground ↗
Examples
- ❌ Incorrect
- ✅ Correct
// an empty interface
interface Foo {}
// an interface with only one supertype (Bar === Foo)
interface Bar extends Foo {}
// an interface with an empty list of supertypes
interface Baz {}
// an interface with any number of members
interface Foo {
name: string;
}
// same as above
interface Bar {
age: number;
}
// an interface with more than one supertype
// in this case the interface can be used as a replacement of an intersection type.
interface Baz extends Foo, Bar {}
Options
This rule accepts the following options:
type Options = [
{
allowSingleExtends?: boolean;
},
];
const defaultOptions: Options = [{ allowSingleExtends: false }];
allowSingleExtends
allowSingleExtends: true will silence warnings about extending a single interface without adding additional members
When Not To Use It
If you don't care about having empty/meaningless interfaces, then you will not need this rule.