locutus/esm/c/ctype/isupper.js

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

export function isupper(c) {
    //      discuss at: https://locutus.io/c/ctype/isupper/
    // parity verified: C 23
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Checks if the character is an uppercase letter (A-Z).
    //       example 1: isupper('A')
    //       returns 1: true
    //       example 2: isupper('a')
    //       returns 2: false
    //       example 3: isupper('5')
    //       returns 3: false
    c = (c + '').charAt(0);
    return /^[A-Z]$/.test(c);
}