JS: Unicode Escape Sequence

By Xah Lee. Date: . Last updated: .

You can use escape sequences to represent Unicode char. For example, "\u03b1" is the same as "α".

There are 2 syntax:

The 6 hexadecimal digit syntax is new in ES2015.

// Unicode escape sequence

console.log ( "\u03b1" === "α"); // true

// works for any Unicode whose codepoint is less than 65536 (that is, 2^16, 16 bits)

// start with “\u” and must be followed by 4 digits of hexadecimal
// Unicode escape sequence

console.log ( "\u{03b1}" === "α" ); // true

// start with “\u” and must be followed by 4 to 6 hexadecimal digits

Here's a example of 6 hexadecimal digits.

console.log (
 "\u{1f602}" === "😂"
);
// true

// 😂
// name: FACE WITH TEARS OF JOY
// codepoint decimal: 128514
// codepoint hexadecimal: 1f602

Unicode escape sequence can be used in:

Within a comment, Unicode escape sequence is ignored.

Reference

ECMAScript® 2016 Language Specification#sec-source-text

ECMAScript® 2016 Language Specification#prod-UnicodeEscapeSequence

Character Topic

  1. JS: String Code Unit vs Code Point
  2. JS: Convert Character To/From Codepoint
  3. JS: String.fromCodePoint
  4. JS: String.fromCharCode
  5. JS: String.prototype.charAt
  6. JS: String.prototype.charCodeAt
  7. JS: String.prototype.codePointAt
  8. JS: Convert Decimal/Hexadecimal
  9. JS: Unicode Escape Sequence

String Topic

  1. JS: String Overview
  2. JS: Template String
  3. JS: String Object
  4. JS: String.prototype
  5. JS: String Code Unit vs Code Point
  6. JS: String Escape Sequence
  7. JS: Unicode Escape Sequence
  8. JS: Source Code Encoding
  9. JS: Allowed Characters in Identifier
  10. JS: Convert String to Number
  11. JS: Encode URL, Escape String
  12. JS: Format Number
  13. JS: JSON
Liket it? Put $5 at patreon.

Or, Buy JavaScript in Depth

If you have a question, put $5 at patreon and message me.