how to lowercase the first letter in javascript code example

Example 1: first letter tuUppercase

const string = "tHIS STRING'S CAPITALISATION WILL BE FIXED."
const string = string[0].toUpperCase() + string.slice(1)

Example 2: javascript string first letter lowercase

// for lowercase on first letter
let s = "This is my string"
let lowerCaseFirst = s.charAt(0).toLowerCase() + s.slice(1)

Example 3: javascript capitalize

myString = 'the quick green alligator...';
myString.replace(/^\w/, (c) => c.toUpperCase());

myString = '    the quick green alligator...';
myString.trim().replace(/^\w/, (c) => c.toUpperCase());