no-object-as-default-parameter.md

Disallow the use of objects as default parameters

💼 This rule is enabled in the ✅ recommended config.

Default parameters should not be passed to a function through an object literal. The foo = {a: false} parameter works fine if only used with one option. As soon as additional options are added, you risk replacing the whole foo = {a: false, b: true} object when passing only one option: {a: true}. For this reason, object destructuring should be used instead.

Fail

const abc = (foo = {a: false}) => {};

function foo({a} = {a: false}) {}

const abc = (foo = {a: false, b: 123}) => {};

Pass

const abc = (foo = {}) => {};

function foo(options) {
	const {a} = {a: false, ...options};
}

const abc = (foo = false) => {};

const foo = ({a = false, b = 123}) => {};