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: Character, Code Unit, 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

JS String

  1. String Overview
  2. Template String
  3. Char, Code Unit, Code Point
  4. String Escape Sequence
  5. Unicode Escape Sequence
  6. String to Number
  7. Encode URL, Escape String
  8. Format Number
  9. Source Code Encoding
  10. Allowed Characters in Identifier
  11. String Object
  12. String.prototype
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