How Do I Replace All Occurrences of a String in Javascript

Javascript is a widely used scripting language that enables the creation of dynamic, interactive web pages.

One of the common tasks that a Javascript developer may need to perform is string manipulation, and specifically replacing all occurrences of a string within another string.

In this tutorial, we will discuss how to replace all occurrences of a string in Javascript with code examples.

Introduction to String Manipulation in Javascript

In Javascript, strings are a sequence of characters enclosed in either single or double quotes.

Strings can be manipulated using various built-in methods, including replace() method.

This method returns a new string with some or all matches of a pattern replaced by a replacement.

By default, the replace() method only replaces the first occurrence of the pattern, however, we can modify the method to replace all occurrences by using a regular expression.

Using Regular Expressions to Replace All Occurrences of a String

A regular expression, also known as a regex, is a pattern that is used to match, locate, and manipulate strings.

By using regular expressions, we can replace all occurrences of a string in Javascript.

To replace all occurrences of a string, we need to use the global (g) flag in the regular expression.

Here is an example of using a regular expression to replace all occurrences of the word “Javascript” with the word “JS”:

let str = "I love Javascript. Javascript is my favorite programming language.";
let regex = /Javascript/g;
let newStr = str.replace(regex, "JS");
console.log(newStr);

Output:

“I love JS. JS is my favorite programming language.”

In the above example, we declared a string str containing the text “I love Javascript. Javascript is my favorite programming language.”.

We then declared a regular expression regex with the pattern “Javascript” and the global (g) flag.

Finally, we used the replace() method to replace all occurrences of the word “Javascript” with the word “JS” and stored the result in the newStr variable.