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JavaScript string replace() Method

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In JavaScript, the replace() method is used to search for a specified substring in a string, and then replace it with another substring.

The replace() method does not change the original string.

replace() Method Syntax: 

str.replace(value1, value2);
  • value1: is the regular expression that is to be replaced
  • value2: is a string that will replace the content of the given string. 

Return Values:

It returns a new string with replaced items.

String replace() Method Example: 

Below is an example of the string.replace() Method. 

javascript




let string = 'GeeksForGeeks';
let newstring = string.replace('GeeksForGeeks', 'GfG');
console.log(newstring);


Output

GfG


Explanation:

  • A string string is assigned the value 'GeeksForGeeks'.
  • The replace() method is called on string, searching for the substring 'GeeksForGeeks' and replacing it with 'GfG'.
  • Since the entire string 'GeeksForGeeks' matches, it is replaced with 'GfG'.
  • The new string 'GfG' is assigned to the variable newstring.
  • newstring is logged to the console.

String replace() Method Example: 

Here the contents of the string GeeksForGeeks will be replaced with gfg. 

javascript




// Assigning a string
let string = 'GeeksForGeeks is a CS portal';
    
// Calling replace() method
let newstring = string.replace(/GeeksForGeeks/, 'gfg');
 
// Printing replaced string
console.log(newstring);


Output

gfg is a CS portal


Explanation:

  • A string string is assigned the value 'GeeksForGeeks is a CS portal'.
  • The replace() method is called on string, using a regular expression to match the substring 'GeeksForGeeks' and replace it with 'gfg'.
  • The first occurrence of 'GeeksForGeeks' in the string is replaced with 'gfg'.
  • The modified string is assigned to the variable newstring.
  • The replaced string newstring is logged to the console.

String replace() Method Example: 

Below is an example of the string.replace() Method. 

javascript




// Taking a regular expression
let re = /GeeksForGeeks/;
 
// Taking a string as input
let string = 'GeeksForGeeks is a CS portal';
 
// Calling replace() method to replace
// GeeksForGeeks from string with gfg
let newstring = string.replace(re, 'gfg');
 
// Printing new string with replaced items
console.log(newstring);


Output

gfg is a CS portal


Explanation:

  • A regular expression re is defined to match the substring 'GeeksForGeeks'.
  • A string string is assigned the value 'GeeksForGeeks is a CS portal'.
  • The replace() method is called on string, using the regular expression re to match the substring 'GeeksForGeeks' and replace it with 'gfg'.
  • The first occurrence of 'GeeksForGeeks' in the string is replaced with 'gfg'.
  • The modified string is assigned to the variable newstring.
  • The replaced string newstring is logged to the console.

We can also replace the same words at multiple places in a string. It is known as a global replacement.

String replace() Method Example: 

This example explains replacing of various similar words in a string.

Javascript




// Assigning a string
let string = 'GeeksForGeeks is a CS portal.' +
    'In GeeksForGeeks we can learn multiple languages.' +
    'geeksForGeeks is a great place.';
 
// Calling replace() method
let newstring = string.replace(/GeeksForGeeks/g, 'Gfg');
 
// Printing replaced string
console.log(newstring);


Output

Gfg is a CS portal.In Gfg we can learn multiple languages.geeksForGeeks is a great place.


Explanation:

  • A multi-line string string is assigned with multiple occurrences of the substring 'GeeksForGeeks'.
  • The replace() method is called on string, using a regular expression with the global flag (/g) to match all occurrences of the substring 'GeeksForGeeks' case-sensitively and replacing them with 'Gfg'.
  • All occurrences of 'GeeksForGeeks' in the string are replaced with 'Gfg'.
  • The modified string is assigned to the variable newstring.
  • The replaced string newstring is logged to the console.

JavaScript string replace() Method – UseCase:

1. JavaScript String replaceAll() Method

The Javascript replaceAll() method returns a new string after replacing all the matches of a string with a specified string or a regular expression. The original string is left unchanged after this operation.

2. How to replace all occurrences of a string in JavaScript ?

To replace all occurrences of a string in JavaScript, you can use the replace() method with a regular expression and the g flag.

We have a complete list of Javascript string methods, to check those please go through this Javascript String Complete reference article.

Supported Browsers: 

  • Google Chrome 1 and above
  • Edge 12 and above
  • Firefox 1 and above
  • Internet Explorer 5.5 and above
  • Opera 4 and above
  • Safari 1 and above


Last Updated : 04 Mar, 2024
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