JS Practice — Built-in Objects

String.prototype.charCodeAt() — NaN for out-of-bounds

📖 Usage Example

const str = 'ABC'
str.charCodeAt(0)   // → 65
str.charCodeAt(1)   // → 66
str.charCodeAt(99)  // → NaN

Use charCodeAt() to get the UTF-16 code unit value of the character at the given index.

String.prototype.charCodeAt() — NaN

When the index is out of bounds, .charCodeAt() returns NaN.

Challenge: Implement codeOrNaN(str, i) and return true when the code is NaN.

codeOrNaN('hi', 99) // → true  (NaN)
codeOrNaN('hi', 0)  // → false (104)

💡 Hints (1)