Answers for "check word is lowercase or uppercase in js"

check if letter is uppercase javascript

const isUpperCase = (string) => /^[A-Z]*$/.test(string)

js if text contains lowercase

function hasLowerCase(str) {
    return str.toUpperCase() != str;
}

console.log("HeLLO: ", hasLowerCase("HeLLO"));
console.log("HELLO: ", hasLowerCase("HELLO"));