Case-insensitive substring search

JavaScript, String · Jul 28, 2022

Checks if a string contains a substring, case-insensitive.

Use the RegExp constructor with the 'i' flag to create a regular expression, that matches the given searchString, ignoring the case.
Use RegExp.prototype.test() to check if the string contains the substring.

const includesCaseInsensitive = (str, searchString) =>
  new RegExp(searchString, 'i').test(str);

includesCaseInsensitive('Blue Whale', 'blue'); // true

Written by Angelos Chalaris

I'm Angelos Chalaris, a JavaScript software engineer, based in Athens, Greece. The best snippets from my coding adventures are published here to help others learn to code.

If you want to keep in touch, follow me on GitHub or Twitter.