synchronous blocking wait delay in react js code example

Example: javascript sleep function

sleep = milliseconds => new Promise(resolve => setTimeout(resolve, milliseconds));

//        V  Must add this async keyword
sayHi = async () => {
  	// V Must include await
	await sleep(1000); // Sleep 1000 milliseconds (1 second)
  	console.log('Hi');
  	// Rest of code...
}