JavaScript RegExp \uXXXX Metacharacter

What You’ll Learn

The \uXXXX escape matches a Unicode character by its four-digit hexadecimal code point. Use it when you need to target a specific symbol—such as ©, é, or ♥—without typing the character directly in your source code.

Introduction

Every character in a JavaScript string has a numeric Unicode code point. The \uXXXX escape lets you refer to that character using exactly four hexadecimal digits after \u—both in string literals and inside regular expressions.

This is especially useful when the character is hard to type, invisible on your keyboard, or when you want your source code to stay ASCII-only while still matching international text, symbols, or control characters by their exact code point.

Understanding the \uXXXX Metacharacter

\uXXXX matches one UTF-16 code unit whose value equals the four hex digits. For example, \u0041 is the letter A (U+0041), and \u00A9 is the copyright sign © (U+00A9).

/\u0041/.test("A");        // true
/\u0041/.test("B");        // false
/\u00A9/.test("© 2026");   // true

"A" === "\u0041";          // true (same in strings)

The escape works identically in regex patterns and JavaScript strings. In a pattern, /\u00E9/ matches the character é just as the literal /é/ would.

How to Use \uXXXX in JavaScript

Use \uXXXX in detection, replacement, validation, and character-class patterns:

/\u00E9/.test("café");              // true
"hello\u2665".match(/\u2665/);     // ["♥"]
"© 2026".replace(/\u00A9/g, "(c)"); // "(c) 2026"
/[\u2665\u2605\u2728]/.test("★");   // true

Combine multiple Unicode escapes inside a character class [...] to match any of several symbols. Use the global flag when replacing every occurrence.

📝 Syntax

\uXXXX          // one Unicode code unit (4 hex digits)
\u0041          // letter A (U+0041)
\u00A9          // copyright © (U+00A9)
[\u2665\u2605]  // heart OR star in a class
/\u{1F600}/u    // emoji 😀 (braced form, needs u flag)

Common patterns

• /\u0041/ — match the letter A by code point.
• /\u00A9/ — detect a copyright symbol.
• /[\u00E0-\u00FF]/ — match Latin accented letters in a range.
• /\u{1F600}/u — match emoji with the braced form and u flag.

Examples Gallery

Open DevTools Console (F12) or use Try-it links. Examples cover basic matching, symbols, accented letters, heart characters, and Unicode character classes.

console.log(/\u0041/.test("A"));     // true
console.log(/\u0041/.test("B"));     // false
console.log(/\u0041/.test("Apple")); // true (starts with A)

true
false
true

const text = "CodeToFun © 2026";

console.log(/\u00A9/.test(text)); // true
console.log(text.match(/\u00A9/)[0]); // "©"

true
©

const word = "café";

console.log(/\u00E9/.test(word));       // true
console.log(word.replace(/\u00E9/g, "e")); // "cafe"

true
cafe

const msg = "I ♥ JavaScript";

const found = msg.match(/\u2665/);
console.log(found[0]); // "♥"
console.log(found.index); // 2

♥
2

const pattern = /[\u2665\u2605\u2728]/g;
const text = "Rate ★★★★★ ♥ sparkle ✨";

const symbols = text.match(pattern);
console.log(symbols.join(" ")); // "★ ★ ★ ★ ★ ♥ ✨"
console.log(symbols.length);    // 7

★ ★ ★ ★ ★ ♥ ✨
7

🚀 Common Use Cases

• International text — match accented letters and non-ASCII characters by code point.
• Symbol validation — detect ©, ™, €, and other special symbols in user input.
• ASCII-safe source — write patterns without embedding non-ASCII characters directly.
• Log parsing — match invisible or rare Unicode characters in exported data.
• Normalization — replace specific Unicode characters with ASCII equivalents.
• Character filtering — allow or block specific symbols using character classes.

Important Considerations

• Exactly four digits — \u41 is invalid; always pad with leading zeros (\u0041).
• BMP limit — single \uXXXX covers U+0000–U+FFFF; emoji above that need \u{...} with the u flag.
• Not the same as \x — \x41 is byte 0x41 (65 = A), but \x cannot reach code points above 255.
• Case insensitive — hex digits A–F can be upper or lower case; \u0041 and \u0041 are equivalent.
• Surrogate pairs — characters above U+FFFF are stored as two UTF-16 code units; match them with two escapes or use \u{...}.

📝 Notes

• \uXXXX requires exactly four hexadecimal digits (0–9, A–F).
• The same escape works in string literals: "\u0041" produces "A".
• For emoji and code points above U+FFFF, use /\u{1F600}/u (braced form with u flag).
• Previous metacharacter: \t horizontal tab.
• Next metacharacter: \v vertical tab.
• Look up code points at the Unicode Character Database or browser DevTools string inspector.

💡 Best Practices