split() in JavaScript

Hello Devs,

If you have landed here then I must say that you have used the JavaScript split() method in your dev journey and if you haven't then do not worry, be with me and let's dive deep into split() method.


The split() method is used to split/break the string at the breakpoint/separator defined and return the remaining characters or string as an element of an array based on the separator (character or string or regex) passed as a first argument in split() method. 🤷‍♂️

split in javascript


str.split(separator, limit)

where the separator can be a single character or string or regex describing where to break the string and push the remaining inside an output array. It is an optional field.

limit is the limit of the breaking points of the string, or you can say the length of an output/returned array. It should be a non-negative number, but if you provide a negative number then it will be ignored and it is treated as an empty value.

NOTE: it is important to note that the original string is unaffected after splitting it.


1. Example with separator

let str = "learn with capscode" str.split() //['learn with capscode'] //if nothing is passed as argument then array is returned with one element and that element will be str str.split("") //['l', 'e', 'a', 'r', 'n', ' ', 'w', 'i', 't', 'h', ' ', 'c', 'a', 'p', 's', 'c', 'o', 'd', 'e'] //If an empty string ("") is passed as an argument, the string is split between each characters. str.split(" ") //['learn', 'with', 'capscode'] //space as separator is passed, so the str is split at each space and the substring got pushed in an output array. str.split("a") //['le', 'rn with c', 'pscode'] //string is split at each 'a' character "one is not 1 and 2 is not two".split(1) //['one is not ', ' and 2 is not two'] console.log(str) //'learn with capscode' //there is no change in the original string

2. Examples with separators & limits.

let str = 'learn with capscode' str.split("",2) //['l', 'e'] //separator is empty string so it will get split after each character and the split number (limit) is 2 so it will split 2 times and the rest will be ignored also the length of returned array will be 2. str.split(" ",2) //['learn', 'with'] //separator is space, so it will get split after each space and the limit value is 2 so it will only split 2 times and the rest will be ignored. str.split(" ", 0)//[] //limit value is 0, hence it will split the str 0 times. str.split(" ", -2) //['learn', 'with', 'capscode'] //limit should be non-negative, but if we put negative limit then it will be ignored and it will be treated as an empty limit value like below one. str.split(" ") //['learn', 'with', 'capscode']

3. Example with separator as regex

3.1. split on multiple keywords

let str = 'CapsCode is a website where you can learn web development'; str.split(/\s+(?:is|can|where)\s+/); //['CapsCode', 'a website', 'you', 'learn web development']

3.2. split the string to count the number of sentences in a paragraph

let paragraph="You are a developer.Do you know JavaScript?If you don't then you can learn it from CapsCode.I hope you love to have a cup of coffee!" paragraph.split(/[.,!,?]/) //['You are a developer', 'Do you know JavaScript', "If you don't then you can learn it from CapsCode", 'I hope you love to have a cup of coffee', '']

Some key points to remember

let str="learn with capscode" str.split(" ","1") //['learn'] //the limit is a string str.split(" ", "abcd") //[] str.split(" ", "") //[] NOTE: "".split("") //[] //string is empty and separator is empty string then the output will be an empty array "".split("a") //[''] //string is empty and separator is non empty, then the returned array will ['']


split() is useful when we want to break/split the string at some specific string or separator, let's say we have some id or token which is separated by underscore (_) like userid_sessionid_authkey and we want to use the userid later in the code.

or let's say we have a user logged in & we have the full name of the user and now we want to show the first character of firstname and the first character of lastname then we can use split like name.split(" ")[0][0]+name.split(" ")[1][0]

and a lot more,

Thank you for reading this far. This is a brief introduction to split method in JavaScript.

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