capitalize first letter #strings #vanillajs

script.js

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

capitalizeFirstLetter('puyih') //'Puyih'
capitalizeFirstLetter('p')      //'P'
capitalizeFirstLetter(0)        //''
capitalizeFirstLetter({})       //''