JSFiddle - React, Tailwind, and code Playground

HTML

<p id='target'></p>

JavaScript

const printMessage = (target, message, frequency) => {
	console.log('COUCOU')
	message.forEach((line, lineIndex) => {
  	const previousCharacters = message.slice(0, lineIndex).join(' ').length
    line.split('').forEach((character, charIndex) => {
    	setTimeout(() => {
      	target.innerHTML = `${target.innerHTML}${character}${charIndex === line.length - 1 ? '<br/>' : ''}`
      }, (previousCharacters + charIndex) * frequency)
    })
  })
}

printMessage(document.getElementById('target'), [
	'Hello World!',
	'How are you ?'
], 100)