JS Practice — Built-in Objects

String.prototype.codePointAt() — vs charCodeAt for BMP

📖 Usage Example

const str = 'Hello'
str.codePointAt(0)     // → 72
'😀'.codePointAt(0)    // → 128512

Use codePointAt() to get the full Unicode code point at a position, correctly handling supplementary characters.

codePointAt vs charCodeAt

For BMP characters, both methods return the same value. For supplementary characters, they differ at position 0.

Challenge: Implement codesMatch(str, pos) that returns true when .codePointAt(pos) equals .charCodeAt(pos).

codesMatch('A', 0)  // → true
codesMatch('😀', 0) // → false

💡 Hints (1)

• BMP code points (0–65535) are the same in both methods. Supplementary code points differ.