Using regular expression engine in content script

From https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Content_scripts

I read that “If a content script does want to use a JavaScript library, then the library itself should be injected as a content script alongside the content script that wants to use it” My code use RegEx object.
r = new RegExp(template, modifier);
What is the library I should add in my manifest file ?
Thanks

You do not need additional library for standard JavaScript functions/Objects etc like Regular Expression.

That note refers to when for example developer wants to inject JQuery library in addition to the normal code.

Thanks. I lost a g modifier in the message from backrgound which resulted in an endless loop.