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JavaScript RegExp \b Metacharacter

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The RegExp \b Metacharacter in JavaScript is used to find a match at the beginning or end of a word. If a match is found it returns the word else it returns NULL. 

Syntax: 

/\b/ 

or

new RegExp("\\b")

Syntax with modifiers:

/\b/g 

or

new RegExp("\\b", "g")

Example 1: This example matches the word “GeeksforGeeks” at the beginning of the string. 

Javascript




function geek() {
    let str1 = "GeeksforGeeks@_123_$";
    let regex4 = /\bgeeksforgeeks/gi;
    let match4 = str1.match(regex4);
 
    console.log("Found " + match4.length
        + " match: " + match4);
}
geek();


Output

Found 1 match: GeeksforGeeks

Example 2: This example matches the word “Geeky” at the beginning and replaces it with the word “GFG”. 

Javascript




function geek() {
    let str1 = "Geeky@128";
    let regex4 = new RegExp("\\bGeeky", "gi");
    let replace = "GFG";
    let match4 = str1.replace(regex4, replace);
    console.log(" New string: " + match4);
}
geek();


Output

 New string: GFG@128

Supported Browsers: The browsers supported by RegExp \b Metacharacter are listed below:

  • Google Chrome
  • Apple Safari
  • Mozilla Firefox
  • Opera
  • Internet Explorer

We have a complete list of Javascript RegExp expressions, to check those please go through this JavaScript RegExp Complete Reference article.

We have a Cheat Sheet on Javascript where we covered all the important topics of Javascript to check those please go through Javascript Cheat Sheet-A Basic guide to JavaScript.  


Last Updated : 29 May, 2023
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