Question 4

Question

Can you explain how to use named capture groups and how to access them in JavaScript?

Answer

Named capture groups add clarity and organization to regular expressions by giving meaningful names to the parts of a string you want to extract.

How They Work:

1. Defining Named Groups: Use parentheses () around the capturing group and name it with a valid identifier (letters, numbers, underscores) preceded by a question mark ?:

   /(?<name>\w+)\s+(?<age>\d+)/

2. Accessing Captures: After using exec(), you can access the captured groups using their names:

   const regex = /(?<name>\w+)\s+(?<age>\d+)/;
   const match = regex.exec("John 30");
   if (match) {
     console.log(match.groups.name); // Output: "John"
     console.log(match.groups.age);   // Output: "30"
   }

Example:

const emailRegex = /(?<username>\w+)\@(?<domain>\w+\.\w+)/;
const email = "[e-mail]";

const match = emailRegex.exec(email);

if (match) {
  console.log("Username:", match.groups.username); // Output: Username: john.doe
  console.log("Domain:", match.groups.domain);   // Output: Domain: example.com
}

Key Advantages:

• Readability: Named groups make your regex patterns much easier to understand and maintain.

• Organization: They clearly label the parts of a string you're capturing, improving code clarity.