What you need to know about variable scope What is a user-defined variable in JavaScript? All JavaScript programming happens in an environment like a web browser, Node, or Bun.js.

As with almost every programming language, JavaScript treats various types of values differently. A string like “Hello world” is very different from a number like 42. But what types are ...

It's been a while since I worked on regexs in JavaScript, but generally the way you do this in most programming languages is to build the regex as a string and then pass it into the regex engine.