#consistent-return

#Configuration

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

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'consistent-return': 'error',
    },
  },
]);

#Rule Details

This rule requires return statements to either always or never specify values.

A function is inconsistent when one return in it hands back a value and another does not, or when it returns a value on one path and runs off the end of its body on another — because falling off the end hands back undefined.

The check applies to each function on its own. A nested function is judged separately from the function that contains it, and the first return reached in a function sets the expectation for the rest of it.

Two shapes are exempt from the "runs off the end" half of the check, because returning a value from them is how a constructor overrides the object being built: a class constructor, and a function whose own name starts with an uppercase letter.

Examples of incorrect code for this rule:

function doSomething(condition) {
  if (condition) {
    return true;
  } else {
    return;
  }
}

function doSomethingElse(condition) {
  if (condition) {
    return true;
  }
}

Examples of correct code for this rule:

function doSomething(condition) {
  if (condition) {
    return true;
  } else {
    return false;
  }
}

function Foo() {
  if (!(this instanceof Foo)) {
    return new Foo();
  }
}

#Options

#treatUndefinedAsUnspecified

When true, return undefined; and return void 0; are read as returning nothing, so they pair with a bare return;. It defaults to false.

Examples of correct code for this rule with { "treatUndefinedAsUnspecified": true }:

{ "consistent-return": ["error", { "treatUndefinedAsUnspecified": true }] }

function doSomething(condition) {
  if (condition) {
    return undefined;
  } else {
    return;
  }
}

Examples of incorrect code for this rule with { "treatUndefinedAsUnspecified": true }:

{ "consistent-return": ["error", { "treatUndefinedAsUnspecified": true }] }

function doSomething(condition) {
  if (condition) {
    return true;
  }
  return undefined;
}

#Original Documentation

https://eslint.org/docs/latest/rules/consistent-return