Limit and Truncate a String to a Given Length in JavaScript and Node.js

When working with text in JavaScript, you may need to limit the number of characters of a string value. For example, the tutorial overview here on Future Studio displays an excerpt of 300 characters providing a short introduction.

This tutorial shows you how to limit a string in JavaScript to a certain number of characters and truncate the string in case it exceeds a given limit.

Node.js Series Overview

Limit a JavaScript String to N Characters

JavaScript provides the String#substring method allowing you to return a part of a given string. This substring is the part between a start and end index. It contains a limited number of characters.

In case the original string’s length exceeds the limit, it returns only the part until the number of characters reaches the given limit:

/**
 * Returns the first `limit` characters from the given `string`.
 *
 * @param {String} string
 * @param {Number} limit
 *
 * @returns {String}
 */
function limit (string = '', limit = 0) {  
  return string.substring(0, limit)
}

const greeting = limit('Hello Marcus', 6)  
// 'Hello '

const greeting = limit('Hello Marcus', 100)  
// 'Hello Marcus'

The limit method returns the original string if its length is shorter than or equal to the given limit. Otherwise, the method cuts off the string value and returns a substring with a length of the given character limit.

Use the @supercharge/strings Package

I’m the maintainer of the @supercharge/strings package providing convenient string utilities. Limiting a string to a certain number of characters is one of the available methods. You may also end a truncated string with additional characters, like :

const Str = require('@supercharge/strings')

const limit = Str('Hello Marcus').limit(6).get()  
// 'Hello '

const limit = Str('Hello Marcus').limit(6, '...').get()  
// 'Hello …'

const limit = Str('Hello Marcus').limit(100, '...').get()  
// 'Hello Marcus'

Enjoy!


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