JavaScript RegExp Non-Word Metacharacter (\W)

What Is \W?

\W matches any single character that is not a word character. Word characters are letters, digits, and underscore ([A-Za-z0-9_]). Spaces, hyphens, and punctuation all match \W.

\w  → letter, digit, or underscore
\W  → everything else (space, -, !, @, …)
\W+ → one or more non-word characters

/\W/.test("hello")      → false
/\W/.test("hello!")     → true
/\W/.test("user_name")  → false  (_ is \w)
/\W/.test("user-name")  → true   (- is \W)

How to Use \W

Use \W when you care about “not a word character” — detect it, strip it, or split on it.

1. Write /\W/ to match one non-word character.
2. Add + for a run of separators (\W+).
3. Use the g flag with replace or match to process every match.
4. Remember: underscore is a word character — it does not match \W.

Pseudocode

pattern has "\W"
read next character ch from the string

if ch is letter, digit, or underscore:
    fail this path
else:
    accept ch as a non-word match

common actions:
  test(str)              → true if any symbol/space/punct exists
  replace(/\W/g, "")     → keep letters, digits, _
  split(/\W+/)           → tokens between separators

Cheat Sheet

Keep these facts handy while cleaning punctuation and symbols.

Live Preview

Run common \W operations on sample strings.

text = "hello"
/\W/.test(text)
→ false

/* letters are word characters */

JavaScript Examples

Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.

console.log(/\W/.test("hello"));      // false
console.log(/\W/.test("hello!"));     // true
console.log(/\W/.test("user_name"));  // false (_ is word char)
console.log(/\W/.test("user-name"));  // true

false
true
false
true

const title = "Hello, World!";
console.log(title.replace(/\W/g, "")); // "HelloWorld"

const email = "[email protected]";
console.log(email.replace(/\W/g, "")); // "useremailcom"

HelloWorld
useremailcom

const csv = "one,two;three four";
console.log(csv.split(/\W+/));
// ["one", "two", "three", "four"]

const tags = "js,regex,pattern";
console.log(tags.split(/\W+/));
// ["js", "regex", "pattern"]

["one", "two", "three", "four"]
["js", "regex", "pattern"]

Performance Notes

Character-class style matches are cheap. Prefer \w when you want word characters directly, and \W when stripping or splitting on everything else is clearer.

Key Takeaways