eslint/no-shadow-restricted-names Correctness

✅ This rule is turned on by default.

What it does

Disallows the redefining of global variables such as undefined, NaN, Infinity, eval, and arguments.

Why is this bad?

Value properties of the Global Object NaN, Infinity, undefined as well as the strict mode restricted identifiers eval and arguments are considered to be restricted names in JavaScript. Defining them to mean something else can have unintended consequences and confuse others reading the code. For example, there’s nothing preventing you from writing:

var undefined = "foo";

Then any code used within the same scope would not get the global undefined, but rather the local version with a very different meaning.

Examples

Examples of incorrect code for this rule:

function NaN() {}

!function(Infinity) {};

var undefined = 5;

try {
} catch (eval) {}

import NaN from "foo";

import { undefined } from "bar";

class Infinity {}

Examples of correct code for this rule:

var Object;

function f(a, b) {}

// Exception: `undefined` may be shadowed if the variable is never assigned a value.
var undefined;

import { undefined as undef } from "bar";

Configuration

This rule accepts a configuration object with the following properties:

reportGlobalThis

type: boolean

default: false

If true, also report shadowing of globalThis.

How to use

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

CLI

oxlint --deny no-shadow-restricted-names

Config (.oxlintrc.json)

{
  "rules": {
    "no-shadow-restricted-names": "error"
  }
}

References

• Rule Source