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typescriptrxjstypescript-eslint

ESLint rule to show missed subscribe call?

Is there any way to get a hint when I forgot to add a subscribe() call on an observable?

// somewhere in some class

function deleteIt(): Observable<any> {
    return httpService.delete('/foo');
}

// some other place

deleteIt();             // 🐛 this statement has no effect and should warn
deleteIt().subscribe(); // this is fine
Solution

  • No, there isn't a rule right now. You might want to propose one in https://github.com/cartant/eslint-plugin-rxjs and/or https://github.com/cartant/eslint-plugin-rxjs-angular.

    Otherwise, you could write your own custom lint rule: https://eslint.org/docs/latest/extend/custom-rules. Presumably you'd want the rule to only apply to values that are the Observable type, so you'll need to use something like typescript-eslint's Typed Rules guide to use TypeScript type information.