JavaScript RegExp [^abc] Character Class

What Is [^abc]?

[^abc] is a negated character class. It matches exactly one character that is not a, b, or c. The ^ must be the first character inside the brackets to mean “not.”

/[^abc]/     → one char that is NOT a, b, or c
/[abc]/      → one of a, b, or c (the opposite)
/[^abc]+/    → one or more chars outside {a,b,c}

"cab".match(/[^abc]/g)  → null
"cat".match(/[^abc]/g)  → ["t"]

^ inside []  → negate the class
^ outside [] → start-of-string anchor

How to Use [^abc]

Write the class in a regex, then use test, match, or replace.

1. Write /[^abc]/ (add g to find every match).
2. Use test() to check if any non-a/b/c character exists.
3. Use match() to collect characters outside the set.
4. List more letters after ^ when you need a bigger exclude set.

Pseudocode

pattern = [^abc]     // "not a, not b, not c"

for each character ch in text:
    if ch is NOT in {a, b, c}:
        ch matches
    else:
        ch does not match

// with + : match the longest run of such characters

Cheat Sheet

Keep these facts handy while writing custom exclude sets.

Live Preview

Pick a sample string and see every match of /[^abc]/g.

text = "cat"
text.match(/[^abc]/g)
→ ["t"]

/* a and c skipped; t is outside {a,b,c} */

JavaScript Examples

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

const notAbc = /[^abc]/;

console.log(notAbc.test("cab"));   // false
console.log(notAbc.test("cat"));   // true
console.log(notAbc.test("Code"));  // true

false
true
true

const text = "a1b!";

console.log(text.match(/[^abc]/g));   // ["1", "!"]
console.log(text.match(/[^abc]+/g));  // ["1", "!"]
console.log("cab".match(/[^abc]/g)); // null

1,!
1,!
null

const text = "backpack";

console.log(text.replace(/[^abc]/g, ""));  // "baac"
console.log(text.replace(/[abc]/g, ""));   // "kpk"
console.log(/[^abc]/.source);               // "[^abc]"

baac
kpk
[^abc]

Performance Notes

Character-class matching is linear in string length for these patterns. Prefer test when you only need a yes/no answer.

Key Takeaways