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eslint/no-empty-pattern Correctness

✅ This rule is turned on by default.

What it does

Disallow empty destructuring patterns.

Why is this bad?

When using destructuring, it’s possible to create a pattern that has no effect. This happens when empty curly braces are used to the right of an embedded object destructuring pattern, such as:

// doesn't create any variables
var {a: {}} = foo;

In this code, no new variables are created because a is just a location helper while the {} is expected to contain the variables to create, such as:

// creates variable b
var {a: { b }} = foo;

In many cases, the empty object pattern is a mistake where the author intended to use a default value instead, such as:

// creates variable a
var {a = {}} = foo;

The difference between these two patterns is subtle, especially because the problematic empty pattern looks just like an object literal.

Examples of incorrect code for this rule:

var {} = foo;
var [] = foo;
var {a: {}} = foo;
var {a: []} = foo;
function foo({}) {}
function foo([]) {}
function foo({a: {}}) {}
function foo({a: []}) {}

Examples of correct code for this rule:

var {a = {}} = foo;
var {a = []} = foo;
function foo({a = {}}) {}
function foo({a = []}) {}

Configuration

This rule accepts a configuration object with the following properties:

allowObjectPatternsAsParameters

type: boolean

default: false

When set to true, this rule allows empty object patterns used directly as function parameters, including parameters defaulted to an empty object literal.

How to use

To enable this rule using the config file or in the CLI, you can use:

Config (.oxlintrc.json)

{
  "rules": {
    "no-empty-pattern": "error"
  }
}

Config (oxlint.config.ts)

import { defineConfig } from "oxlint";

export default defineConfig({
  rules: {
    "no-empty-pattern": "error",
  },
});

CLI

oxlint --deny no-empty-pattern

Version

This rule was added in v0.0.3.

References

• Rule Source
• Upstream rule docs
• Open rule in Oxc Playground