Explore JavaScript regular expressions: learn about regex history, create patterns with special characters, parse data, and match passwords/emails, gaining comprehensive text processing skills.

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Regular Expressions, also known as Regex, come in handy in a multitude of text processing scenarios. Regex defines a search pattern using symbols and allows you to find matches within strings. The applications of this span from software engineering to data science and beyond.

In this course, you will begin with an introduction to regex, its history, and various types of regular expressions. 

You will then learn how to create your own regular expressions using various techniques and special characters. In the latter half of the course, you will explore RegExp Objects, how to parse data, turn phrases into an array of strings, and lastly password and email pattern matching.

By the end of this course, you will be a regular expressions expert.

JavaScript Regular Expressions in Detail

# Solution #1

Alright, ready on your side? 

The first solution we could think of is the following:

This is a simple text file
with multiple lines that are only delimited by a new line character.

Some lines are short.
Others have so many words that take up more than one.


const fs = require("fs")

function regExparser(txt) {
  let arrContent = txt.replace(/(.+)/g, '"$1",')

  let myCode = `let myArray = [${arrContent}]`
  return myCode
}

fs.readFile("./sample.txt", "utf8", (err, content) => {
  if(err) console.error(err)
  console.log(content.toString())
  console.log(regExparser(content.toString()))
})

Assuming a text file with the exact same content as the one shown on the diagram above, here is the output that we get:

Notice how the output shows the code we wanted. However, we’re also being affected by the whitespace. In fact, that line is simply an empty line that starts and ends with an EOL character. This is why we’re seeing an empty string as an item inside the array for that position. For the regular expression, that line doesn’t match (because we used the + sign, stating we need *at least* one character, other than the EOL, to be present).

# Solution #2

So, to solve this, we’ll need a bit of extra work, like this:





Let's look at the solutions to the exercise given in the previous lesson.


The Beginning of Regular Expressions

The Anatomy of Regular Expressions

The RegExp Object

Thinking in Regular Expressions

Regular Expressions in the Wild

Wrapping Up

Solution: Turning a List of Phrases Into an Array of Strings

Solution #1