default-param-last

Enforce default parameters to be last.

Examples

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

.eslintrc.cjs

module.exports = {
  "rules": {
    // Note: you must disable the base rule as it can report incorrect errors
    "default-param-last": "off",
    "@typescript-eslint/default-param-last": "error"
  }
};

Try this rule in the playground ↗

Options

See eslint/default-param-last options.

Resources

• Rule source
• Test source

^{Taken with ❤️ from ESLint core}