check to see if work is uppercase javascript

1function isUpper(str) {
2    return !/[a-z]/.test(str) && /[A-Z]/.test(str);
3}
4
5isUpper("FOO"); //true
6isUpper("bar"); //false
7isUpper("123"); //false
8isUpper("123a"); //false
9isUpper("123A"); //true
10isUpper("A123"); //true
11isUpper(""); //false
12

1const isUpperCase = (string) => /^[A-Z]*$/.test(string)
2

1var word = 'apple' //Expected: false
2
3//Use word[0] to grap the first letter
4if (word[0] == word[0].toUpperCase()) {
5  //Word is uppercase
6} else {
7  //Word is not uppercase
8}

1var strings = 'this iS a TeSt 523 Now!';
2var i=0;
3var character='';
4while (i <= strings.length){
5    character = strings.charAt(i);
6    if (!isNaN(character * 1)){
7        alert('character is numeric');
8    }else{
9        if (character == character.toUpperCase()) {
10            alert ('upper case true');
11        }
12        if (character == character.toLowerCase()){
13            alert ('lower case true');
14        }
15    }
16    i++;
17}
18