locutus/php/strings/ord.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ord = ord;
function ord(string) {
    //      discuss at: https://locutus.io/php/ord/
    // parity verified: PHP 8.3
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //     bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
    //     improved by: Brett Zamir (https://brett-zamir.me)
    //        input by: incidence
    //          note 1: Unlike PHP (which returns 0-255), this implementation
    //          note 1: supports Unicode code points via surrogate pairs
    //       example 1: ord('K')
    //       returns 1: 75
    const str = string + '';
    const code = str.charCodeAt(0);
    if (code >= 0xd800 && code <= 0xdbff) {
        // High surrogate (could change last hex to 0xDB7F to treat
        // high private surrogates as single characters)
        const hi = code;
        if (str.length === 1) {
            // This is just a high surrogate with no following low surrogate,
            // so we return its value;
            return code;
            // we could also throw an error as it is not a complete character,
            // but someone may want to know
        }
        const low = str.charCodeAt(1);
        return (hi - 0xd800) * 0x400 + (low - 0xdc00) + 0x10000;
    }
    if (code >= 0xdc00 && code <= 0xdfff) {
        // Low surrogate
        // This is just a low surrogate with no preceding high surrogate,
        // so we return its value;
        return code;
        // we could also throw an error as it is not a complete character,
        // but someone may want to know
    }
    return code;
}