htmlfy

HTML formatter yo! Prettify, minify and more!

htmlfy is a fork of html-formatter. A lot of the processing logic has been preserved, and full credit for that goes to the original author. I've made the following major enhancements.

• Fully typed.
• Converted to ESM.
• Added configuration options.
• Added support for custom HTML elements (web components)
• Lots of refactoring.
• Made it go brrr fast.

Install

npm install htmlfy

API

Most projects will only need to use prettify and/or minify.

Prettify

Turn single-line or ugly HTML into highly formatted HTML. This is a wrapper for all other functions, except trimify, and then it adds indentation.

import { prettify } from 'htmlfy'

const html = `<main class="hello   there world"><div>Welcome to htmlfy!  </div></main>`
console.log(prettify(html))
/*
<main class="hello there world">
  <div>
    Welcome to htmlfy!
  </div>
</main>
*/

Minify

Turn well-formatted or ugly HTML into a single line of HTML.

This feature is not a replacement for compressors like htmlnano, which focus on giving you the smallest data-size possible; but rather, it simply removes tabs, returns, and redundant whitespace.

import { minify } from 'htmlfy'

const html = 
`<main class="hello there world">
  <div>
    Welcome to htmlfy!
  </div>
</main>`
console.log(minify(html))
/*
<main class="hello there world"><div>Welcome to htmlfy!</div></main>
*/

Closify

This is done when using prettify, but you can use it in a one-off scenario if needed.

Ensure void elements are "self-closing".

import { closify } from 'htmlfy'

const html = `<br><input type="text">`
console.log(closify(html))
/*
<br /><input type="text" />
*/

Entify

This is done when using prettify, but you can use it in a one-off scenario if needed.

Enforce entity characters for textarea content. This also performs basic minification on textareas before setting entities. When running this function as a standalone, you'll likely want to pass minify as true for full minification of the textarea. The minification does not process any other tags.

import { entify } from 'htmlfy'

const html = `<main class="hello   there world"><div>Welcome to htmlfy!  </div></main><textarea  >

Did   you know that 3 >   2?

This is another paragraph.   


</textarea><textarea class="  more  stuff  ">    </textarea>`
console.log(entify(html, true))
/*
<main class="hello   there world"><div>Welcome to htmlfy!  </div></main><textarea>Did you know that 3 &gt; 2?&#13;&#13;This is another paragraph.</textarea><textarea class="more stuff"></textarea>
*/

Trimify

Trim leading and trailing whitespace for whatever HTML element(s) you'd like. This is a standalone function, which is not run with prettify by default.

import { trimify } from 'htmlfy'

const html = `<div>
Hello World
</div>`
console.log(trimify(html, [ 'div' ]))
/* <div>Hello World</div> */

Default Import

If needed, you can use a default import for htmlfy.

import * as htmlfy from 'htmlfy'

console.log(htmlfy.prettify('<main><div>Hello World</div></main'))

Common JS Import

Although meant to be an ESM module, you can import using require.

const { prettify } = require('htmlfy')

Configuration

These configuration options can only be passed to prettify.

Default config:

{
  content_wrap: 0,
  ignore: [],
  ignore_with: '_!i-£___£%_',
  strict: false,
  tab_size: 2,
  tag_wrap: 0,
  trim: []
}

Content Wrap

Wrap text content at a certain character-width breakpoint. Default is 0, which does not wrap.

import { prettify } from 'htmlfy'

const html = '<div>Lorem ipsum dolor sit amet consectetur adipiscing elit. Quisque faucibus ex sapien vitae pellentesque sem placerat. In id cursus mi pretium tellus duis convallis.</div>'
console.log(prettify(html, { content_wrap: 40 }))
/*
<div>
  Lorem ipsum dolor sit amet consectetur
  adipiscing elit. Quisque faucibus ex
  sapien vitae pellentesque sem placerat.
  In id cursus mi pretium tellus duis
  convallis.
</div>
*/

Ignore

Tell htmlfy to not process some elements and leave them as-is.

import { prettify } from 'htmlfy'

const html = `
<main><div>Hello World</div></main>
<style>
body {
  width: 100
}
</style>`
console.log(prettify(html, { ignore: [ 'style' ] }))
/*
<main>
  <div>
    Hello World
  </div>
</main>
<style>
body {
  width: 100;
}
</style>
*/

Ignore With

You can pass in your own string, for ignoring elements, if the default is actually being used in your ignored elements.

prettify(html, { ignore: [ 'p' ], ignore_with: 'some-string-that-wont-be-in-your-ignored-elements' })

Strict

If set to true, removes comments and ensures void elements are not self-closing.

import { prettify } from 'htmlfy'

const html = `<main><br /><div><!-- Hello World --></div></main>`
console.log(prettify(html, { strict: true }))
/*
<main>
  <br>
  <div></div>
</main>
*/

Tab Size

Determines the number of spaces, per tab, for indentation. For sanity reasons, the valid range is between 1 and 16.

import { prettify } from 'htmlfy'

const html = `<main class="hello   there world"><div>Welcome to htmlfy!  </div></main>`
console.log(prettify(html, { tab_size: 4 }))
/*
<main class="hello there world">
    <div>
        Welcome to htmlfy!
    </div>
</main>
*/

Tag Wrap

Wrap and prettify attributes within opening tags and void elements if they're overall length is above a certain character width. Default is 0, which does not wrap.

In the below example, the <input> element is well over 40 characters long, so it's wrapped and prettified.

import { prettify } from 'htmlfy'

const html = `<form><input id="email-0" type="email" title="We need your email for verification." name="email" required /></form>`
console.log(prettify(html, { tag_wrap: 40 }))
/*
<form>
  <input
    id="email-0"
    type="email"
    title="We need your email for verification."
    name="email"
    required
  />
</form>
*/

Trim

Trim leading and trailing whitespace within textarea elements, since all whitespace is preserved by default.

import { prettify } from 'htmlfy'

const html = '<textarea>    Hello World    </textarea>'
console.log(prettify(html, { trim: [ 'textarea' ]}))
/*<textarea>Hello&nbsp;World</textarea>*/

For compatibility and possible future expansion, we require declaring an array with the value 'textarea', as opposed to using something like { trim: true }. Passing in additional HTML element values has no real effect, since we already trim whitespace for all other elements.