Index: JavaScript RegEx

Regular Expressions (Regex) are powerful search patterns used to find, match, and manipulate text.
Think of Regex as a smart filter โ it can detect and extract information based on patterns, not just specific words.
For example:
- You can find all email addresses in a document.
- You can check if a phone number has the right format.
- You can replace all extra spaces, punctuation, or unwanted characters in a paragraph.
Regex works across almost every modern programming language โ Python, JavaScript, Java, C#, PHP, and many others โ because pattern matching is a universal need.
โจ Why Use Regex?
Regular expressions are used when you need precision and flexibility in text searching or text cleaning.
Letโs see where Regex becomes a superhero:
| Scenario | Task | Example |
|---|---|---|
| Validation | Check if an input looks like an email, phone number, or date. | user@example.com โ
|
| Searching | Find all mentions of a word, even if itโs written differently. | โdogโ, โDogโ, โDOGโ ๐ถ |
| Cleaning Data | Remove unwanted characters or extra spaces. | Hello!!! โ Hello |
| Extraction | Pick out useful parts of text, like URLs or hashtags. | #learning, #python |
| Formatting | Rearrange text to a specific structure. | 2025-10-25 โ 25/10/2025 |
In short, Regex gives you the power to talk directly to patterns within text โ not just exact characters.
In this series of lessons, weโll uncover how RegEx works in JavaScript, one piece at a time โ from simple matches to capturing groups, look-aheads, and dynamic replacements.
By the end, you wonโt just โuseโ regex โ youโll speak its language fluently. Ready to unlock the code behind the patterns? Letโs dive in! ๐