# is-var-name

> Check if a string can be used as a JavaScript variable name

Latest version **2.0.0** (published 2018-02-19) · ISC license · 0 weekly downloads

## Install

```sh
npm install is-var-name
pnpm add is-var-name
yarn add is-var-name
bun add is-var-name
```

## Health

**Score 20/100 (F)** — status: abandoned.

Positive: esm support; no vulnerabilities.

Warnings: low downloads; no types.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 2.0.0 |
| Published | 2018-02-19 |
| First published | 2014-11-25 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | ESM + CommonJS |
| Dependencies | 0 |
| Unpacked size | 4.5 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 14 |
| Maintainers | shinnn |
| Keywords | var, variable, let, const, identifier, check, character, javascript, ecmascript, specification, validation, spec, string |

## Links

- npm: https://www.npmjs.com/package/is-var-name
- Repository: https://github.com/shinnn/is-var-name
- Homepage: https://github.com/shinnn/is-var-name#readme
- Issues: https://github.com/shinnn/is-var-name/issues
- npm.io page: https://npm.io/package/is-var-name

## Alternatives

- [@sindresorhus/slugify](https://npm.io/package/@sindresorhus/slugify.md) — 3.7M weekly downloads
- [solid-js](https://npm.io/package/solid-js.md) — 2.7M weekly downloads
- [expo-glass-effect](https://npm.io/package/expo-glass-effect.md) — 2.5M weekly downloads
- [nanoassert](https://npm.io/package/nanoassert.md) — 780.8K weekly downloads
- [@ffmpeg/ffmpeg](https://npm.io/package/@ffmpeg/ffmpeg.md) — 529.5K weekly downloads

## Recent versions

- 2.0.0 (latest) — 2018-02-19
- 2.0.0-0 (next) — 2018-02-19
- 1.0.0 — 2014-11-25

## README

# is-var-name

[![npm version](https://img.shields.io/npm/v/is-var-name.svg)](https://www.npmjs.com/package/is-var-name)
[![Build Status](https://travis-ci.org/shinnn/is-var-name.svg?branch=master)](https://travis-ci.org/shinnn/is-var-name)
[![Coverage Status](https://img.shields.io/coveralls/shinnn/is-var-name.svg)](https://coveralls.io/r/shinnn/is-var-name)

Check if a string can be used as a [JavaScript variable name](https://es5.github.io/x7.html#x7.6)

```javascript
isVarName('foo'); //=> true
isVarName('f o o'); //=> false
```

## Installation

[Use](https://docs.npmjs.com/cli/install) [npm](https://docs.npmjs.com/getting-started/what-is-npm).

```
npm install is-var-name
```

## API

```javascript
import isVarName from 'is-var-name';
```

### isVarName(*name*)

*name*: `string`  
Return: `boolean`

It returns `true` if [the string can be used as a valid JavaScript identifier name](https://mathiasbynens.be/notes/javascript-identifiers). If not, or the argument is not a string, it returns `false`.

```javascript
isVarName('______________'); //=> true
isVarName('å'); //=> true

isVarName('123'); //=> false
isVarName('↑→↓←'); //=> false
isVarName('_;'); //=> false
isVarName(''); //=> false

isVarName(['foo']); //=> false
isVarName(); //=> false
```

## Another solution

Instead of this module, you can use [the regular expression that matches valid variable names](https://gist.github.com/mathiasbynens/6334847#file-ecmascript-6-js).

### Regular expression pros

*is-var-name* uses [`Function` constructor](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Function) but regular expression doesn't.

According to [the ESLint documentation](https://eslint.org/docs/rules/no-new-func), `new Function()` is:

> considered by many to be a bad practice due to the difficult in debugging and reading these types of functions.

### Regular expression cons

Since the regular expression is too long ([about 16,000 characters](https://gist.githubusercontent.com/mathiasbynens/6334847/raw/4b78d62a29da1f340956aa102dffa6c4ac7e620e/ecmascript-6.js)), it increases the file size of your library or application.

## License

[ISC License](./LICENSE) © 2018 Shinnosuke Watanabe

---
_Source: https://npm.io/package/is-var-name · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._