JavaScript RegExp ?! Quantifier
Last Updated :
10 Dec, 2024
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The RegExp ?!m Quantifier in JavaScript is used to find the match of any string which is not followed by a specific string m.
// 3-digits not followed by any numbers
const str = "123Geeks12345@";
const regex = /\d{3}(?!\d)/g;
const match = str.match(regex);
console.log(match);
Output
[ '123', '345' ]
Syntax
/?!m/ Example 1: Matching the words 'Geeks' not followed by 123 in the whole string.
let str = "Geeks for 123 Geeks@";
let regex = /Geeks(?!123)/g;
let match = str.match(regex);
console.log("Found " + match.length
+ " matches: " + match);
Output
Found 2 matches: Geeks,Geeks
Example 2: Replacing the word '128' with '#' symbol.
let str = "@128Geek128";
let regex = new RegExp("128(?!ee)", "gi");
let replace = "#";
let match = str.replace(regex, replace);
console.log("New string: " + match);
Output
New string: @#Geek#
Recommended Links:
- JavaScript RegExp Complete Reference
- JavaScript Cheat Sheet-A Basic guide to JavaScript
- JavaScript Tutorial
