Enforce default parameters to be last (default-param-last)

Rule Details

This rule extends the base eslint/default-param-last rule. It adds support for optional parameters.

❌ Incorrect

/* eslint @typescript-eslint/default-param-last: ["error"] */

function f(a = 0, b: number) {}
function f(a: number, b = 0, c: number) {}
function f(a: number, b?: number, c: number) {}
class Foo {
  constructor(public a = 10, private b: number) {}
}
class Foo {
  constructor(public a?: number, private b: number) {}
}

✅ Correct

/* eslint @typescript-eslint/default-param-last: ["error"] */

function f(a = 0) {}
function f(a: number, b = 0) {}
function f(a: number, b?: number) {}
function f(a: number, b?: number, c = 0) {}
function f(a: number, b = 0, c?: number) {}
class Foo {
  constructor(public a, private b = 0) {}
}
class Foo {
  constructor(public a, private b?: number) {}
}

How to use

{
  // note you must disable the base rule as it can report incorrect errors
  "default-param-last": "off",
  "@typescript-eslint/default-param-last": ["error"]
}

Options

See eslint/default-param-last options.

Taken with ❤️ from ESLint core

Attributes

• ✅ Recommended
• 🔧 Fixable
• 💭 Requires type information