freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/regular-expressions/use-capture-groups-to-search-and-replace.english.md

id, title, challengeType

id	title	challengeType
587d7dbb367417b2b2512bab	Use Capture Groups to Search and Replace	1

Description

Searching is useful. However, you can make searching even more powerful when it also changes (or replaces) the text you match. You can search and replace text in a string using .replace() on a string. The inputs for .replace() is first the regex pattern you want to search for. The second parameter is the string to replace the match or a function to do something.

let wrongText = "The sky is silver.";
let silverRegex = /silver/;
wrongText.replace(silverRegex, "blue");
// Returns "The sky is blue."

You can also access capture groups in the replacement string with dollar signs ($).

"Code Camp".replace(/(\w+)\s(\w+)/, '$2 $1');
// Returns "Camp Code"

Instructions

Write a regex so that it will search for the string "good". Then update the replaceText variable to replace "good" with "okey-dokey".

Tests

tests:
  - text: You should use <code>.replace()</code> to search and replace.
    testString: assert(code.match(/\.replace\(.*\)/), 'You should use <code>.replace()</code> to search and replace.');
  - text: Your regex should change <code>"This sandwich is good."</code> to <code>"This sandwich is okey-dokey."</code>
    testString: assert(result == "This sandwich is okey-dokey." && replaceText === "okey-dokey", 'Your regex should change <code>"This sandwich is good."</code> to <code>"This sandwich is okey-dokey."</code>');
  - text: You should not change the last line.
    testString: assert(code.match(/result\s*=\s*huhText\.replace\(.*?\)/), 'You should not change the last line.');

Challenge Seed

let huhText = "This sandwich is good.";
let fixRegex = /change/; // Change this line
let replaceText = ""; // Change this line
let result = huhText.replace(fixRegex, replaceText);

Solution

let huhText = "This sandwich is good.";
let fixRegex = /good/g; // Change this line
let replaceText = "okey-dokey"; // Change this line
let result = huhText.replace(fixRegex, replaceText);