README

truncate-html

Truncate html string(even contains emoji chars) and keep tags in safe. You can custom ellipsis sign, ignore unwanted elements and truncate html by words.

Notice This is a node module depends on cheerio can only run on nodejs. If you need a browser version, you may consider truncate or nodejs-html-truncate.

const truncate = require('truncate-html')
truncate('<p><img src="xxx.jpg">Hello from earth!</p>', 2, { byWords: true })
// => <p><img src="xxx.jpg">Hello from ...</p>

Installation

npm install truncate-html
or
yarn add truncate-html

Try it online

Click https://npm.runkit.com/truncate-html to try.

API

/**
 * truncate html
 * @method truncate(html, [length], [options])
 * @param  {String|CheerioStatic}         html    html string to truncate, or  existing cheerio instance(aka cheerio $)
 * @param  {Object|number}  length how many letters(words if `byWords` is true) you want reserve
 * @param  {Object|null}    options
 * @param  {Boolean}        [options.stripTags] remove all tags, default false
 * @param  {String}         [options.ellipsis] ellipsis sign, default '...'
 * @param  {Boolean}        [options.decodeEntities] decode html entities(e.g. convert `&amp;` to `&`) before
 *                                                   counting length, default false
 * @param  {String|Array}   [options.excludes] elements' selector you want ignore
 * @param  {Number}         [options.length] how many letters(words if `byWords` is true)
 *                                           you want reserve
 * @param  {Boolean}        [options.byWords] if true, length means how many words to reserve
 * @param  {Boolean|Number} [options.reserveLastWord] how to deal with when truncate in the middle of a word
 *                                1. by default, just cut at that position.
 *                                2. set it to true, with max exceed 10 letters can exceed to reserver the last word
 *                                3. set it to a positive number decide how many letters can exceed to reserve the last word
 *                                4. set it to negetive number to remove the last word if cut in the middle.
 * @param  {Boolean}        [options.trimTheOnlyWord] whether to trim the only word when `reserveLastWord` < 0
 *                                if reserveLastWord set to negetive number, and there is only one word in the html string,
 *                                 when trimTheOnlyWord set to true, the extra letters will be cutted if word's length longer
 *                                 than `length`.
 *                                see issue #23 for more details
 * @param  {Boolean}        [options.keepWhitespaces] keep whitespaces, by default continuous
 *                                spaces will be replaced with one space
 *                                set it true to reserve them, and continuous spaces will count as one
 * @return {String}
 */
truncate(html, [length], [options])
// and truncate.setup to change default options
truncate.setup(options)

Default options

{
  byWords: false,
  stripTags: false,
  ellipsis: '...',
  decodeEntities: false,
  keepWhitespaces: false,
  excludes: '',
  reserveLastWord: false,
  keepWhitespaces: false
}

You can change default options by using truncate.setup

e.g.

truncate.setup({ stripTags: true, length: 10 })
truncate('<p><img src="xxx.jpg">Hello from earth!</p>')
// => Hello from

or use existing cheerio instance

import * as cheerio from 'cheerio'
truncate.setup({ stripTags: true, length: 10 })
// truncate option `decodeEntities` will not work
//    you should config it in cheerio options by yourself
const $ = cheerio.load('<p><img src="xxx.jpg">Hello from earth!</p>', {
  /** set decodeEntities if you need it */
  decodeEntities: true
  /* any cheerio instance options*/
})
truncate($)
// => Hello from

Notice

Typescript support

This lib is written with typescript and has a defination file along with it. You may need to update your tsconfig.json by adding "esModuleInterop": true to the compilerOptions if you encounter some typing errors, see #19.

{
  "compilerOptions": {
    "esModuleInterop": true
  }
}

About final string length

If the html string content's length is shorter than options.length, then no ellipsis will be appended to the final html string. If longer, then the final string length will be options.length + options.ellipsis. And if you set reserveLastWord to true of none zero number, the final string will be various.

About html comments

All html comments  will be removed

About dealing with none alphabetic languages

When dealing with none alphabetic languages, such as Chinese/Japanese/Korean, they don't separate words with whitespaces, so options byWords and reserveLastWord should only works well with alphabetic languages.

And the only dependency of this project cheerio has an issue when dealing with none alphabetic languages, see Known Issues for details.

Using existing cheerio instance

If you want to use existing cheerio instance, truncate option decodeEntities will not work, you should set it in your own cheerio instance:

var html = '<p><img src="abc.png">This is a string</p> for test.'
const $ = cheerio.load(`${html}`, {
  decodeEntities: true
  /** other cheerio options */
})
truncate($, 10)

Examples

var truncate = require('truncate-html')

// truncate html
var html = '<p><img src="abc.png">This is a string</p> for test.'
truncate(html, 10)
// returns: <p><img src="abc.png">This is a ...</p>

// truncate string with emojis
var string = '<p>poo 💩💩💩💩💩<p>'
truncate(string, 6)
// returns: <p>poo 💩💩...</p>

// with options, remove all tags
var html = '<p><img src="abc.png">This is a string</p> for test.'
truncate(html, 10, { stripTags: true })
// returns: This is a ...

// with options, truncate by words.
//  if you try to truncate none alphabet language(like CJK)
//      it will not act as you wish
var html = '<p><img src="abc.png">This is a string</p> for test.'
truncate(html, 3, { byWords: true })
// returns: <p><img src="abc.png">This is a ...</p>

// with options, keep whitespaces
var html = '<p>         <img src="abc.png">This is a string</p> for test.'
truncate(html, 10, { keepWhitespaces: true })
// returns: <p>         <img src="abc.png">This is a ...</p>

// combine length and options
var html = '<p><img src="abc.png">This is a string</p> for test.'
truncate(html, {
  length: 10,
  stripTags: true
})
// returns: This is a ...

// custom ellipsis sign
var html = '<p><img src="abc.png">This is a string</p> for test.'
truncate(html, {
  length: 10,
  ellipsis: '~'
})
// reutrns: <p><img src="abc.png">This is a ~</p>

// exclude some special elements(by selector), they will be removed before counting content's length
var html = '<p><img src="abc.png">This is a string</p> for test.'
truncate(html, {
  length: 10,
  ellipsis: '~',
  excludes: 'img'
})
// reutrns: <p>This is a ~</p>

// exclude more than one category elements
var html =
  '<p><img src="abc.png">This is a string</p><div class="something-unwanted"> unwanted string inserted ( ´•̥̥̥ω•̥̥̥` ）</div> for test.'
truncate(html, {
  length: 20,
  stripTags: true,
  ellipsis: '~',
  excludes: ['img', '.something-unwanted']
})
// returns: This is a string for~

// handing encoded characters
var html = '<p>&nbsp;test for &lt;p&gt; encoded string</p>'
truncate(html, {
  length: 20,
  decodeEntities: true
})
// returns: <p> test for &lt;p&gt; encode...</p>

// when set decodeEntities false
var html = '<p>&nbsp;test for &lt;p&gt; encoded string</p>'
truncate(html, {
  length: 20,
  decodeEntities: false // this is the dafault value
})
// returns: <p>&nbsp;test for &lt;p...</p>

// and there may be a surprise by setting `decodeEntities` to true  when handing CJK characters
var html = '<p>&nbsp;test for &lt;p&gt; 中文 string</p>'
truncate(html, {
  length: 20,
  decodeEntities: true
})
// returns: <p> test for &lt;p&gt; &#x4E2D;&#x6587; str...</p>
// to fix this, see below for instructions

for More usages, check truncate.spec.ts

Known issues

Known issues about handing CJK(Chinese/Japanese/Korean) characters when set the option decodeEntities to true.

You have seen the option decodeEntities, it's really magic! When it's true, encoded html entities will be decoded automatically, so & will be treat as a single character. This is probably what we want. But, if there are CJK characters in the html string, they will be replaced by characters like ö(still count as one character when truncating) in the final html you get. That's confused.

To fix this, you have two choices:

keep the option decodeEntities false, but & will treat as five characters.
modify cheerio's source code: find out the function getInverse in the file ./node_modules/cheerio/node_modules/entities/lib/decode.js, comment out the last line .replace(re_nonASCII, singleCharReplacer);.

Credits

Thanks to:

@calebeno es6 support and unit tests
@aaditya-thakkar emoji truncating support

Usage no npm install needed!