What are Regular Expressions* ?

Answer 1

Do you mean 'regular expression'? (regex) https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

Answer 2

In your post you made a mistake. Regular expressions - right question.
In JavaScript, a regular expression is simply a type of object that is used to match character combinations in strings.

Answer 3

My experience with regular expressions is that they are hard to master :-)

Answer 4

We also have a regex tutorial written by Emerson Prado. Remember to check it out!

https://www.sololearn.com/learn/9704/?ref=app