JS Practice — Built-in Objects

String.prototype.length — emoji length is 2 code units

📖 Usage Example

'hello'.length    // → 5
''.length         // → 0
'😀'.length       // → 2

The length property returns the number of UTF-16 code units in the string.

String.prototype.length — Emoji

Emoji like 😀 are encoded as a surrogate pair (two UTF-16 code units), so '😀'.length === 2.

Challenge: Implement emojiLength() that returns the length of the emoji '😀'.

emojiLength() // → 2

💡 Hints (2)

• Emoji characters outside the Basic Multilingual Plane use two UTF-16 code units (a surrogate pair).
• `"😀".length === 2` even though it looks like a single character.