🔰escape sequence

JS ⟩ value ⟩ primitive ⟩ String ⟩ escape sequence

'\x4A'       // 'J'     ('\xXX')
'\u222B'     // '∫'     ('\uXXXX')
'\u{1F639}'  // '😹'    ('\u{0 ~ 10FFFF}'}

⭐️ 重點

escape sequence	code points
\xXX … (XX = 00~FF, 2 hex digits)	(Basic Latin and Latin-1 Supplement) (= ISO-8859-1) U+0000 ~ U+00FF
\uXXXX (XXXX= 0000 ~ FFFF, 4 hex digits)	(Basic Multilingual Plane) U+0000 ~ U+FFFF
\u{X}…\u{XXXXXX} (X…XXXXXX, 1~6 hex digits)	(the entirety of Unicode) U+0000 ~ U+10FFFF

👥 相關

• code point(s) are used in escape sequences.

💈範例

• replit ⟩ escape sequence

// ⭐ Basic Latin
// '\xXX': XX = 00 ~ FF (0 ~ 255, 2^8 code points)
'\x4A',       // 'J'
'\x7A',       // 'z'

// ⭐ BMP (Baisc Multilingual Plane / Plane 0)
// '\uXXXX': XXXX = 0000 ~ FFFF (0 ~ 65535, 2^16 code points)
'\u222B',     // '∫'

// ⭐ entire Unicode (Plane 0 ~ 16)
// '\u{X}' ~ '\u{XXXXXX}': 0 ~ 10FFFF (17 * 2^16 = 1,114,112 code points)
'\u{7A}',     // 'z'
'\u{121}',    // 'ġ'
'\u{1F639}',  // '😹'

• other examples：octal escape sequence

📘 手冊

• String ⟩ escape sequences

• Grammar and types ⟩ Using special characters in strings