#unified-signatures

#Configuration

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

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

Disallow overloads that can be combined into one signature with a union, optional parameter, or rest parameter.

#Rule details

Multiple overloads make an API harder to read when they differ only in a single parameter type or in one parameter that can be omitted. This rule reports those signatures and recommends expressing the difference directly.

Examples of incorrect code for this rule:

function parse(value: string): void;
function parse(value: number): void;

interface Factory {
  create(): Result;
  create(options?: Options): Result;
}

Examples of correct code for this rule:

function parse(value: string | number): void;

interface Factory {
  create(options?: Options): Result;
}

function convert(value: string): string;
function convert(value: number): number;

The last pair is allowed because its return types differ.

#Options

The rule accepts an optional object:

{
  "ignoreDifferentlyNamedParameters": false,
  "ignoreOverloadsWithDifferentJSDoc": false
}

#ignoreDifferentlyNamedParameters

When true, overloads whose corresponding parameters have different names are not combined.

#ignoreOverloadsWithDifferentJSDoc

When true, overloads with different preceding block comments are not combined.

#Original documentation

• typescript-eslint: unified-signatures
• Source code
• Tests