How To Replace All Commas In A String In Javascript?

Posted on by Tom Joseph
Replace all commas in a string using javascript

A JavaScript string is an object representing and manipulating a sequence of characters. Thanks to this nature, we can treat a string as an array of substrings. In this tutorial, we will break down the methods to replace all commas in a string using JavaScript and provide additional information.

Replace All Commas In A String In Javascript

Substrings substitution using replaceAll()

JavaScript offers a handful of pre-defined methods to aid your work around strings. One of the quickest solutions to Replace all commas in a String in JavaScript is using replaceAll() method. We will provide you the syntax of this method below:

replaceAll (pattern, replacement)

Parameters:

  • pattern: A string or an object or a Regular Expression with the global (g) flag
  • replacement: Be a string or a function. For functions, it can be invoked for every match and its return value as replacement text. Various replacement patterns are supported.

This method will pass a string after modification as its return type and not mutate the initial one. Hence, you need to assign your target string to the returned value.

Our code snippet using this method should be as such:

let mystr = "apple, pen, ink, coal";
myst = mystr.replaceAll (',',"");

console.log(mystr);

Output

apple pen ink coal

In this example, we replace all commas with empty substrings. Whatever replacement is to be passed in the method is at your disposal.

Using Regular Expression with replace()

Compared to the previous replaceAll(), this method lacks the apparent word “All” in its function name. Up to what it’s called, when you pass a substring to replace(), only the first instance that matches the pattern is replaced.

// passing a substring
let str = "checks,the,first,instance";

str = str.replace('-', ' ');
console.log(str);

Output

checks the,first,instance

To make replace() checks for all occurrences, we recommend using Regular Expression.

Regular Expressions are patterns used to parallel character combinations within strings in JavaScript. They also are treated as objects and are supported with numerous work methods.

Regular Expressions can be created either by literal notations or constructors.

// literal notations
const pttrn = /,/g;

// regular expression constructors
const pttrn = new RegExp(/,/, 'g');

Flags that specify the search of these expressions should be attached at the end of literal notations or the second argument of RegExp() syntax.

Each Regular Expression above will give the same output:

Str = str.replace (pttrn," ");

Output

checks the first instance

Implementing conversion between a string and an array

In this approach, we will attempt to divide a string into an array of substrings by negating its commas. Next, these substrings will be assembled into a new string following the exact order given a separator.

JavaScript has suitable methods designed for these scenarios.

string.split(separator, limit)

Parameters:

  • Separator: (optional) A string or an object, typically a Regular Expression
  • Limit: (optional) A non-negative integer indicating the number of substrings to include in the to-be-returned array. All leftover text after the limit will be removed.
    • An array may contain fewer members than limit 
    • If limit = 0 , split() returns []
array.join (separator)

Parameter:

  • The separator is optional. This parameter specifies what will separate each pair of elements in the array. If empty, it will automatically use commas.

We will execute an example below on how to remove all commas from a string:

let str = "no, commas, in, this, string";
str = str.split(/,/).join("");
console.log(str);

Output

no commas in this string

Summary

Most common approaches to replace all commas in a string in JavaScript would be replaceAll(), replace(), split(), join(), etc. Thanks to their being predefined. However, learners are encouraged to be creative to build more diverse strategies in different situations.

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