JSFiddle - React, Tailwind, and code Playground

JavaScript

var letters = ['a', 'b', 'c', 'A', 'B', 'C', '(', ')', '+', '-', '~', '*'];

for (var i = 0; i<letters.length; i++) {
    if (letters[i] === letters[i].toUpperCase()
        && letters[i] !== letters[i].toLowerCase()) {
        console.log(letters[i] + ": " + true);
    } else {
        console.log(letters[i] + ": " + false);
    }
}