javascript change all instances of character in string to uppercase code example

Example 1: capitalize first carater js

const capitalize = (s) => {
  if (typeof s !== 'string') return ''
  return s.charAt(0).toUpperCase() + s.slice(1)
}

capitalize('flavio') //'Flavio'
capitalize('f')      //'F'
capitalize(0)        //''
capitalize({})       //''

Example 2: make first letter uppercase

const publication = "freeCodeCamp";
publication[0].toUpperCase() + publication.substring(1);