Is Text or Binary?

Determine if a filename and/or buffer is text or binary. Smarter detection than the other solutions.

Determination works like so:

1. Extension Check: If filename is available, check if any of its extensions (from right to left) are an [text extension](https://github.com/bevry/textextensions) or a [binary extension](https://github.com/bevry/binaryextensions), this is near instant.
2. Contents Check: If no filename was provided, or the extension check was indeterminate, then check the contents of the buffer.

The extension check will check each of the filename's extensions, from right to left. This is done as certain applications utilise multiple extensions for transformations, such as `app.x.y` may tell a compiler to transform from `x` format to `y` format, in this case perhaps `x` is not a recognized extension but `y` is, in which case we can make use of that to provide superior accuracy and convenience compared to just checking the rightmost extension.

The contents check (with the default options) will check 24 bytes at the start, middle, and end of the buffer. History has shown that checking all three locations is mandatory for accuracy, and that anything less is not accurate. This technique offers superior performance while still offering superior accuracy. Alternatives generally just do 1000 bytes at the start, which is slower, and inaccurate.

One cannot just do the contents check alone because UTF16 characters are indistinguishable from binary which would return an inaccurate result, hence why the combination is necessary for accuracy, with performance for known extensions a side-effect.

As such, this library's combination of extension check (if filename is provided), then contents check (if buffer is provided), offers superior performance and accuracy to alternatives.

Ever since 2012, this module's superior accuracy and performance has been essential to the operation of [DocPad](https://docpad.org) and its other dependents.

## Usage

[Complete API Documentation.](http://master.istextorbinary.bevry.surge.sh/docs/)

```typescript
import { isText, isBinary, getEncoding } from 'istextorbinary'
```

or

```javascript
const { isText, isBinary, getEncoding } = require('istextorbinary')
```

then

```javascript
isText(aFilename) // returns true if a text file otherwise false, checks only filename
isText(null, aBuffer) // returns true if a text file otherwise false, checks only buffer
isText(aFilename, aBuffer) // returns true if a text file otherwise false, checks filename then buffer
isText(null, null) // returns null

isBinary(aFilename) // returns true if a binary file otherwise false, checks only filename
isBinary(null, aBuffer) // returns true if a binary file otherwise false, checks only buffer
isBinary(aFilename, aBuffer) // returns true if a binary file otherwise false, checks filename then buffer
isBinary(null, null) // returns null

getEncoding(aBuffer) // returns 'binary' if it contained non-utf8 characters, otherwise returns 'utf8'
```


Install

npm
 (https://npmjs.com)

- Install: npm install --save istextorbinary
- Import: import * as pkg from ('istextorbinary')
- Require: const pkg = require('istextorbinary')

Skypack
 (https://www.skypack.dev)

``` html
<script type="module">
    import * as pkg from '//cdn.skypack.dev/istextorbinary@^6.0.0'
</script>
```


unpkg
 (https://unpkg.com)

``` html
<script type="module">
    import * as pkg from '//unpkg.com/istextorbinary@^6.0.0'
</script>
```


jspm
 (https://jspm.io)

``` html
<script type="module">
    import * as pkg from '//dev.jspm.io/istextorbinary@6.0.0'
</script>
```


Editions (https://editions.bevry.me)

This package is published with the following editions:

- istextorbinary/source/index.ts is TypeScript (https://www.typescriptlang.org/) source code with Import (https://babeljs.io/docs/learn-es2015/#modules) for modules
- istextorbinary/edition-browsers/index.js is TypeScript (https://www.typescriptlang.org/) compiled against ES2020 (https://en.wikipedia.org/wiki/ECMAScript#11th_Edition_–_ECMAScript_2020) for web browsers with Import (https://babeljs.io/docs/learn-es2015/#modules) for modules
- istextorbinary aliases istextorbinary/edition-es2019/index.js
- istextorbinary/edition-es2019/index.js is TypeScript (https://www.typescriptlang.org/) compiled against ES2019 (https://en.wikipedia.org/wiki/ECMAScript#10th_Edition_-_ECMAScript_2019) for Node.js (https://nodejs.org) 10 || 12 || 14 || 16 with Require (https://nodejs.org/dist/latest-v5.x/docs/api/modules.html) for modules
- istextorbinary/edition-es2019-esm/index.js is TypeScript (https://www.typescriptlang.org/) compiled against ES2019 (https://en.wikipedia.org/wiki/ECMAScript#10th_Edition_-_ECMAScript_2019) for Node.js (https://nodejs.org) 12 || 14 || 16 with Import (https://babeljs.io/docs/learn-es2015/#modules) for modules

History

Discover the release history by heading on over to the HISTORY.md file. (https://github.com/bevry/istextorbinary/blob/master/HISTORY.md#files)

Contribute

Discover how you can contribute by heading on over to the CONTRIBUTING.md file. (https://github.com/bevry/istextorbinary/blob/master/CONTRIBUTING.md#files)

Backers

Maintainers

These amazing people are maintaining this project:

- Benjamin Lupton (https://balupton.com) — view contributions (https://github.com/bevry/istextorbinary/commits?author=balupton)
- Michael Mooring (https://github.com/mikeumus) — view contributions (https://github.com/bevry/istextorbinary/commits?author=mikeumus)
- Rob Loach (https://github.com/robloach) — view contributions (https://github.com/bevry/istextorbinary/commits?author=robloach)

Sponsors

No sponsors yet! Will you be the first?

Contributors

These amazing people have contributed code to this project:

- Benjamin Lupton (https://balupton.com) — view contributions (https://github.com/bevry/istextorbinary/commits?author=balupton)
- Ian Sibner (https://github.com/sibnerian) — view contributions (https://github.com/bevry/istextorbinary/commits?author=sibnerian)
- Kukhyeon Heo (https://github.com/sainthkh) — view contributions (https://github.com/bevry/istextorbinary/commits?author=sainthkh)
- Michael Mooring (https://github.com/mikeumus) — view contributions (https://github.com/bevry/istextorbinary/commits?author=mikeumus)
- Rob Loach (https://github.com/robloach) — view contributions (https://github.com/bevry/istextorbinary/commits?author=robloach)
- Sean (https://github.com/AlbinoDrought) — view contributions (https://github.com/bevry/istextorbinary/commits?author=AlbinoDrought)
- shinnn (https://github.com/shinnn) — view contributions (https://github.com/bevry/istextorbinary/commits?author=shinnn)

Discover how you can contribute by heading on over to the CONTRIBUTING.md file. (https://github.com/bevry/istextorbinary/blob/master/CONTRIBUTING.md#files)

License

Unless stated otherwise all works are:

- Copyright © 2012+ Bevry Pty Ltd (http://bevry.me)
- Copyright © 2011 Benjamin Lupton (https://balupton.com)

and licensed under:

- MIT License (http://spdx.org/licenses/MIT.html)

