StringcodePointAt

The method `String.prototype.codePointAt()` is a built-in JavaScript function that returns the Unicode code point value of a specific character in a string. Introduced in ECMAScript 2015 (ES6), it addresses limitations in the older `charCodeAt()` method by correctly handling surrogate pairs, which are used to represent characters outside the Basic Multilingual Plane (BMP) in UTF-16 encoding.

The function takes a single argument, `position`, which specifies the index of the character in the string. If the character at the given position is part of a surrogate pair, `codePointAt()` returns the full Unicode code point value (a number between 0 and 0x10FFFF). Otherwise, it returns the code point of the character at that position. If the position is out of bounds, it returns `undefined`.

For example, calling `codePointAt(0)` on the string `"👨‍👩‍👧‍👦"` (a single emoji family) returns `0x1F468`, the full Unicode code point for the emoji, rather than the partial values that `charCodeAt()` would return for surrogate pairs.

This method is particularly useful when working with strings containing characters outside the BMP, such as emojis, CJK Unified Ideographs, or other special symbols. It ensures accurate handling of Unicode values, which is essential for proper text processing, encoding, and display in modern web applications. Unlike `charCodeAt()`, which only returns values for BMP characters, `codePointAt()` provides consistent behavior across the entire Unicode range.