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 or a binary extension, 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 and its other dependents.

Usage

Complete API Documentation.

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

or

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

then

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

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

Deno

import * as pkg from 'https://unpkg.com/istextorbinary@^9.5.0/edition-deno/index.ts'

Skypack

<script type="module">
    import * as pkg from '//cdn.skypack.dev/istextorbinary@^9.5.0'
</script>

unpkg

<script type="module">
    import * as pkg from '//unpkg.com/istextorbinary@^9.5.0'
</script>

jspm

<script type="module">
    import * as pkg from '//dev.jspm.io/[email protected]'
</script>

Editions

This package is published with the following editions:

• istextorbinary aliases istextorbinary/index.cjs which uses the Editions Autoloader to automatically select the correct edition for the consumer's environment
• istextorbinary/source/index.ts is TypeScript source code with Import for modules
• istextorbinary/edition-browsers/index.js is TypeScript compiled against ES2022 for web browsers with Import for modules
• istextorbinary/edition-es2022/index.js is TypeScript compiled against ES2022 for Node.js 14 || 16 || 18 || 20 || 21 with Require for modules
• istextorbinary/edition-es2017/index.js is TypeScript compiled against ES2017 for Node.js 6 || 8 || 10 || 12 || 14 || 16 || 18 || 20 || 21 with Require for modules
• istextorbinary/edition-es5/index.js is TypeScript compiled against ES5 for Node.js 4 || 6 || 8 || 10 || 12 || 14 || 16 || 18 || 20 || 21 with Require for modules
• istextorbinary/edition-es2017-esm/index.js is TypeScript compiled against ES2017 for Node.js 12 || 14 || 16 || 18 || 20 || 21 with Import for modules
• istextorbinary/edition-types/index.d.ts is TypeScript compiled Types with Import for modules
• istextorbinary/edition-deno/index.ts is TypeScript source code made to be compatible with Deno

History

Discover the release history by heading on over to the HISTORY.md file.

Backers

Code

Discover how to contribute via the CONTRIBUTING.md file.

Authors

• Benjamin Lupton — Accelerating collaborative wisdom.

Maintainers

• Benjamin Lupton — Accelerating collaborative wisdom.

Contributors

• Benjamin Lupton — view contributions
• Ian Sibner — view contributions
• Kukhyeon Heo — view contributions
• Michael Duane Mooring — view contributions
• Rob Loach — view contributions
• Sean — view contributions
• shinnn — view contributions

Finances

Sponsors

• Andrew Nesbitt — Software engineer and researcher
• Balsa — We're Balsa, and we're building tools for builders.
• Codecov — Empower developers with tools to improve code quality and testing.
• Poonacha Medappa
• Rob Morris
• Sentry — Real-time crash reporting for your web apps, mobile apps, and games.
• Syntax — Syntax Podcast

Donors

• Andrew Nesbitt
• Armen Mkrtchian
• Balsa
• Chad
• Codecov
• dr.dimitru
• Elliott Ditman
• entroniq
• GitHub
• Hunter Beast
• Jean-Luc Geering
• Michael Duane Mooring
• Michael Harry Scepaniak
• Mohammed Shah
• Mr. Henry
• Nermal
• Pleo
• Poonacha Medappa
• Rob Morris
• Robert de Forest
• Sentry
• ServieJS
• Skunk Team
• Syntax
• WriterJohnBuck

License

Unless stated otherwise all works are:

• Copyright © Benjamin Lupton

and licensed under:

• Artistic License 2.0