is lowercase javascript code example

Example 1: javascript lowercase string

var str = "My Big Boy!"
var res = str.toLowerCase(); //res is "my big boy!"

Example 2: javascript check if all capital letter

function isUpper(str) {
    return !/[a-z]/.test(str) && /[A-Z]/.test(str);
}

isUpper("FOO"); //true
isUpper("bar"); //false
isUpper("123"); //false
isUpper("123a"); //false
isUpper("123A"); //true
isUpper("A123"); //true
isUpper(""); //false

Example 3: javascript lowercase string

var str = "ExaMple";
var res = str.toLowerCase();
output res -> "example"

Example 4: how to check string uppercase or lowersace using regex javascript

var regex = /^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[!#\*\?])(?=.{8,})/;