#strict-void-return

#Configuration

import { defineConfig, ts } from '@rslint/core';

export default defineConfig([
  ts.configs.recommended,
  {
    rules: {
      '@typescript-eslint/strict-void-return': 'error',
    },
  },
]);

#Rule Details

Disallow passing a value-returning function in a position accepting a void function. TypeScript permits a function returning a value to be used where a void-returning function is expected — callbacks can return any value and it is silently discarded — but it hides several common mistakes: forgotten awaits on promise-returning callbacks, generators or async functions misused as fire-and-forget event handlers, and accidental dead values from arrow shorthands. This rule reports any value-returning function used in a context that expects a function whose return type is void. It checks function arguments, JSX attribute values, array elements, assignments, variable initializers, object properties, class members (against extended base classes and implemented interfaces), and return statements.

Examples of incorrect code for this rule:

const getNothing: () => void = () => 2137;

declare function takesCallback(cb: () => void): void;
takesCallback(async () => {
  const response = await fetch('https://api.example.com/');
});

takesCallback(function* () {
  yield 'Hello';
});

['Alice', 'Bob'].forEach(name => `Hello, ${name}!`);

class Foo {
  cb() {
    console.log('foo');
  }
}
class Bar extends Foo {
  cb() {
    return 'bar';
  }
}

interface Foo {
  cb(): void;
}
class Bar implements Foo {
  cb() {
    return 'cb';
  }
}

Examples of correct code for this rule:

const getNothing: () => void = () => {};

declare function takesCallback(cb: () => void): void;
takesCallback(() => {
  void (async () => {
    const response = await fetch('https://api.example.com/');
  })();
});

takesCallback(() => {
  function* gen() {
    yield 'Hello';
  }
  for (const _ of gen());
});

['Alice', 'Bob'].forEach(name => console.log(`Hello, ${name}!`));

class Foo {
  cb() {
    console.log('foo');
  }
}
class Bar extends Foo {
  cb() {
    super.cb();
    console.log('bar');
  }
}

interface Foo {
  cb(): void;
}
class Bar implements Foo {
  cb() {
    console.log('cb');
  }
}

#Options

#allowReturnAny

Type: boolean — Default: false

When false (default), a function returning any is treated the same as any other non-void return — for example, fn(() => JSON.parse('{}')) is reported. When true, functions returning any are accepted in void positions. Useful for codebases where untyped values flow through callbacks intentionally.

Examples of correct code with { "allowReturnAny": true }:

{ "@typescript-eslint/strict-void-return": ["error", { "allowReturnAny": true }] }

declare function fn(cb: () => void): void;
fn(() => JSON.parse('{}'));
fn(() => {
  return someUntypedApi();
});

#Original Documentation

• typescript-eslint strict-void-return