How word character is interpreted in character class?

Question

\\w - stands for [A-Za-z0-9_] Character class

But i am not able to understand how it is interpreted inside character class.

So when

Answer 1

I believe that the main difference between both your examples is the location of your - character. What's happening here is that in this example:

let test = (str) => /^[A-Za-z0-9_-~]+$/.test(str)

console.log(test("T|"))

It's evaluated as a range, like so:

let test = (str) => /^[_-~]+$/.test(str)

console.log(test("|"))

will return true.

Where in this one:

let test = (str) => /^[\w-~]+$/.test(str)

console.log(test("T|"))

Since \w is a set of characters in and of itself, it's evaluating the character - by itself.

The position of - and it's surrounding can make a huge difference in how it's interpreted.

You could avoid that situation, altogether, by moving it to the end, like so:

let test = (str) => /^[A-Za-z0-9_~-]+$/.test(str)

console.log(test("T|"))

which will return false