Understanding JavaScript RegExp Basics

Regular Expressions in JavaScript

JavaScript regular expressions use test and exec, with common patterns.

Introduction to Regular Expressions

Regular expressions (RegExp) in JavaScript are patterns used to match character combinations in strings. They can be used to perform all types of text search and text replace operations.

Creating a Regular Expression

There are two ways to create a RegExp object in JavaScript:

Literal notation: Consists of a pattern enclosed between slashes.
Constructor function: Uses the RegExp() constructor.

Using test() Method

The test() method executes a search for a match between a RegExp and a specified string. It returns true or false.

Using exec() Method

The exec() method executes a search for a match in a specified string. Unlike test(), it returns a result array or null if no match is found.

Common Patterns in Regular Expressions

Here are some common patterns used in regular expressions:

\d: Matches any digit (equivalent to [0-9]).
\w: Matches any alphanumeric character (equivalent to [a-zA-Z0-9_]).
\s: Matches any whitespace character (spaces, tabs, etc.).
^: Matches the beginning of the string.
$: Matches the end of the string.
*: Matches 0 or more occurrences of the preceding character.
+: Matches 1 or more occurrences of the preceding character.

JS RegExp