Trouble splitting a string in JavaScript using regular expressions

I am VERY new to regex in js and having a very hard time manipulating them to do what I am looking for.

I have a series of strings that I am trying to strip of unusual characters, spaces, newlines, etc. and put them into arrays where each entry is a word consisting of only alphanumeric characters.

For example:

let testString = "this*is " + "an" +" test string "
test = testString.split(/W/)  
console.log(test)

Yields [ 'this', 'is', 'a', '', 'test', 'string', '' ]

But ideally I would like it to yield [ 'this', 'is', 'a', 'test', 'string']

I can achieve the desired result by adding .filter(word => word !== '') to the end, but I am wondering if there is a way to do this using only regular expressions? Also would it be necessary to add a global flag to the regex?

Thanks in advance for any input!