Text Processing with JavaScript

Recipe 31

Extracting a Matched Value with the Capturing Group

Task

Suppose you need to search for a file with a .pdf extension and extract only the filename without the extension. Typically, regular expressions return the entire matched string, but you want a solution that enables you to identify and extract a specific part of the matched string for further processing.

Solution

Place a pair of parentheses around the specific part of the pattern that you want to extract:

part_2/capturing_group_p2/capturing_group_p2_ex1.js

const re = /\b(\w+)\.pdf\b/;
const str = "Please download data_p2x53.pdf";

const result = str.match(re);

if (result) {
  console.log(result[1])
} else {
  console.error("No match found.");