https://github.com/shinnn/is-var-name

Check if a string can be used as a JavaScript variable name
https://github.com/shinnn/is-var-name

boolean ecmascript javascript language validation validator

Last synced: 26 days ago
JSON representation

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

• Host: GitHub
• URL: https://github.com/shinnn/is-var-name
• Owner: shinnn
• License: isc
• Created: 2014-11-25T03:57:53.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2019-04-05T11:48:41.000Z (over 5 years ago)
• Last Synced: 2024-10-11T22:26:46.761Z (about 1 month ago)
• Topics: boolean, ecmascript, javascript, language, validation, validator
• Language: JavaScript
• Homepage: https://npm.runkit.com/is-var-name
• Size: 46.9 KB
• Stars: 15
• Watchers: 1
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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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.com/shinnn/is-var-name.svg?branch=master)](https://travis-ci.com/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/about-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 - 2019 Shinnosuke Watanabe