How to Replace All Occurrences of a String in JavaScript

Introduction

Replacing all occurrences of a string in JavaScript (Official Page) is a common task that developers may need to perform. Fortunately, JavaScript provides a number of methods for doing this, including the replace() method, which can be used to replace all occurrences of a string with another string. In this article, we’ll look at how to use the replace() method to replace all occurrences of a string in JavaScript.

Using the replace() Method

The replace() method is a string method that can be used to replace all occurrences of a string with another string. The syntax for the replace() method is as follows:

string.replace(searchValue, replaceValue)

The replace() method takes two parameters: the searchValue and the replaceValue. The searchValue is the string that you want to replace, and the replaceValue is the string that you want to replace it with. For example, if you wanted to replace all occurrences of the word “cat” with the word “dog”, you could use the following code:

let myString = 'The cat is in the hat';let newString = myString.replace('cat', 'dog');console.log(newString); // The dog is in the hat

The replace() method is case-sensitive, so if you wanted to replace all occurrences of the word “Cat” with the word “Dog”, you would need to use the following code:

let myString = 'The Cat is in the Hat';let newString = myString.replace('Cat', 'Dog');console.log(newString); // The Dog is in the Hat

Using Regular Expressions

The replace() method can also be used with regular expressions. Regular expressions are a powerful tool for matching patterns in strings. For example, if you wanted to replace all occurrences of the word “cat” with the word “dog”, regardless of whether it is capitalized or not, you could use the following code:

let myString = 'The Cat is in the Hat';let newString = myString.replace(/cat/gi, 'dog');console.log(newString); // The Dog is in the Hat

The “/cat/gi” part of the code is a regular expression. The “/” indicates the start of the regular expression, the “cat” is the pattern that we are looking for, the “g” indicates that we want to search for the pattern globally (i.e. in the entire string), and the “i” indicates that we want to ignore the case (i.e. we want to match both “cat” and “Cat”).

Summary

In this article, we looked at how to use the replace() method to replace all occurrences of a string in JavaScript. We also looked at how to use regular expressions to replace all occurrences of a string, regardless of case. With the replace() method and regular expressions, you can easily replace all occurrences of a string in JavaScript.

If you want to read more about JavaScript, look at article about javascript closures and how to remove elements from array in js

Easy way to use javascript is with libraries, like jquery (very popular for years)

Here is tutorial how to check if element is hidden in jquery