String.prototype.codePointAt()

codePointAt(index)

Returns: number | undefined · Added in vES2015 · Updated March 13, 2026 · String Methods

string unicode code-point encoding

The codePointAt method returns a non-negative integer representing the Unicode code point at the given index. Unlike charCodeAt, it correctly handles surrogate pairs—characters outside the Basic Multilingual Plane (BMP) that require two 16-bit units in JavaScript strings.

Syntax

codePointAt(index)

Parameters

Parameter	Type	Default	Description
index	number	—	The position in the string. Returns undefined if index is out of bounds or negative.

Examples

Basic usage

const str = "Hello, 🌍";
console.log(str.codePointAt(0));  // 72 (H)
console.log(str.codePointAt(1));  // 101 (e)
console.log(str.codePointAt(5));  // 32 (space)
console.log(str.codePointAt(7));  // 128751 (🌍)

Handling surrogate pairs

const emoji = "😀";
console.log(emoji.codePointAt(0));  // 128512
console.log(emoji.charCodeAt(0));   // 55357 (incorrect - returns high surrogate)

// Spread operator (iterates by code points)
[..."A😀Z"].forEach(cp => console.log(cp.codePointAt(0)));
// 65
// 128512
// 90

Converting code points back to characters

const codePoint = 128512; // 😀
console.log(String.fromCodePoint(codePoint));  // 😀

// Process each code point
const str = "Hello 🌍";
const codePoints = [...str].map(char => char.codePointAt(0));
console.log(codePoints);  // [72, 101, 108, 108, 111, 32, 128751]

Common Patterns

Iterate over code points safely

function getCodePoints(str) {
  return [...str].map(char => char.codePointAt(0));
}

console.log(getCodePoints("abc"));      // [97, 98, 99]
console.log(getCodePoints("a🌀c"));    // [97, 128300, 99]

Check if a string contains surrogate pairs

function hasSurrogates(str) {
  return [...str].some(char => char.codePointAt(0) > 0xFFFF);
}

console.log(hasSurrogates("hello"));    // false
console.log(hasSurrogates("hello😀")); // true

Compare with charCodeAt

const str = "A🎉";
console.log(str.charCodeAt(1));     // 55349 (high surrogate)
console.log(str.codePointAt(1));    // 128397 (correct 🎉)

// charCodeAt treats each 16-bit unit separately
// codePointAt treats the string as code points

Process text containing emojis

function reverseString(str) {
  return [...str].reverse().join("");
}

console.log(reverseString("Hello😀World")); // dlroW😀olleH
// Without spreading, reversing would break the emoji:
// "Hello😀World".split("").reverse().join("") // "dlroW口olleH" (broken)