JavaScript Comparison Between String.slice() Vs String.substr()
mobile app development

JavaScript Comparison of String.slice() Vs String.substr() Vs String.substring()

Slice, Substr, and Substring in JavaScript differs in various aspects.

JavaScript Comparison of String.slice() Vs String.substr() Vs String.substring()

With this article on JavaScript, we will be clearing out your confusion in using String.slice() vs String.substr() vs String.substring() together or separately.  But first, we will start by explaining the key differences in the JavaScript strings i.e. substr and substring.

JavaScript basically has two string methods that are:

  1. Substr
  2. Substring

The confusion mainly arises in these two JavaScript strings because they look very identical at the first glance, as both of these string methods also return a substring from a given string.

So, what separates these similar two string methods…

What tells apart these JavaScript string methods are their 'Second Parameters' because both of the numbers are expecting two different outcomes.

For example:

If we are using a 'substr' the second parameter is the number of the characters to include in the substring. Like -

var s = "string";

s.substr(1, 3); // would return 'tri'


var s = "another example";

s.substr(3, 7); // would return 'ther ex'

But when we are using a 'substring', then the second parameter is the first index that is not to include. Like -

var s = "string";

s.substring(1, 3); // would return 'tr'


var s = "another example";

s.substring(3, 7); // would return 'ther'

String.slice() vs String.substr() vs String.substring()

The methods slice(), substring(), and substr() are the methods that extract parts of a string and then return the extracted parts in a new string. Also, all of these methods do not change the original string from which they extract.

For the slice method i.e. slice(), it can take these two arguments:

Argument #1 - With 'begin' the position of where to begin the extraction is required. The position of the first character starts at 0 and it can use the negative values to specify the exact location from the end of the string.

Argument #2 - For 'end', the position where to end the extraction is optional to mention. Once omitted, the slice() will then select all the characters from the 'start' position to the end of the string and can also use the negative numbers to select from the end of the main string.


var numbers="0123456789";

console.log(numbers.slice(2,4));   // shows 23

console.log(numbers.slice(-7,-3)); // shows 3456

For the substring method i.e. substring(), it can take these two arguments:

Argument #1 - Starting with 'from' it is required to mention where to extraction from and the first character's index will be set as 0.

Argument #2 - Beginning with 'to', it is optional to mention where the end of extraction will be. Once omitted, it will extract all the rest of the string itself.


console.log(numbers.substring(-3,5));  // shows 01234

console.log(numbers.substring(NaN,5)); // shows 01234

console.log(numbers.substring(-3));    // shows 0123456789

For the substr method i.e. substr(), it can take these two arguments:

Argument #1 - With the 'start' the extraction will begin and the first character will begin at an index of 0. For extracting the characters from the end of the string, the negative start numbers will be used.

Argument #2 - For the 'length', the mentioning of the number of characters to extract is optional. And if is it omitted, the rest of the string will be extracted automatically.


console.log(numbers.substr(3)); // shows 3456789

console.log(numbers.substr(-3));// shows 789

Main difference between String.slice() and String.substring()

If the startIndex > endIndex (startIndex greater than endIndex) then the slice() will run an empty string but substring() will swap those parameters. And if startIndex < endIndex (endIndex greater than startIndex) then slice() will consider it as string.length-index whereas substring() will treat them as a zero i.e. 0.

Do let us know if you agree with the above-mentioned differences between JavaScript slice(), substr() and substring(), by commenting down below.

Twinkle <span>Product Strategist</span>
Written By
Twinkle Product Strategist

Twinkle is an experienced business and marketing consultant of the mobile app industry. She advocates perfect branding to the latest tech releases. She is passionate about writing well-researched reports to help the app owners and the mobile app industry audience. Also, she has a vibrant touch that goes well in her writing as well.

mobile app development

Are You A Developer? Google Is Launching A Certification Program For You

4 min read  

On 5th September, celebrating Google Developer Day Europe 2017, the search engine announced the launch of Mobile Web Specialist Certification Program on Google Developers Blog, calling out all the web developers to showcase their skills. The certification is aimed at filtering out the ones that suit

mobile app development

What Are Different Types Of Logistics App Development Technologies

4 min read  

It is a well-established fact that logistics are responsible for driving many businesses worldwide. This becomes highly significant when we look at the fact of how many entrepreneurs think of widening their footprints across different geographic locations. This is the part where the transportation a

mobile app development

Hybrid or Native: Which Should You Prefer For Your Enterprise?

4 min read  

Nowadays Startups are highly dependent upon the mobile application for their success. For any business in its initial state, it is almost inevitable to skip the involvement of mobile app strategy in marketing plans. But there is a big dilemma regarding the selection of the native and hybrid app. The

mobile app development

Are You Using 12-Factor App Methodology ?

4 min read  

In today’s world, most of the SAAS services are being deployed as the web applications. This action requires the development team to deal with many processes to successfully deploy the app. If you are a member of such team then you must know that the process isn't easy, the team encounters