Asynchronous functions challenge

Solution for a challenge of the Rocketseat's Launchbase JS course

Source

Part of the challenges on the link (original - portuguese):
https://github.com/rocketseat-education/bootcamp-launchbase-desafios-06/blob/master/desafios/06-1-mini-desafios.md

Begin of translation:"

Asynchronous functions

Case1

Implement a function that takes a number as a parameter and, after x milliseconds (within a range of 1 to 100 ms. Use setTimeout and the floor and random functions from the Math library, show twice the received parameter in the console. Then call this function 5 times. Ex.:

function printDouble(number){
  setTimeout(
    () => {
      console.log(number * 2)
    }, 
    Math.floor(Math.random() * 100) + 1
  )
}

function printAll(){
  printDouble(5)
  printDouble(10)
  printDouble(22)
  printDouble(1)
  printDouble(89)
}

printAll()

Without carrying out any processing, it is easy to see that the order of values shown in the console when calling the printAll() function is random and does not respect the order in which the functions are called. Therefore, to resolve this issue, handle setTimeout asynchronism using callback, Promise and async/await.

(Tip: when dealing with Promise, return a new Promise and use the resolve parameter).

Case 2

Now, change your function a little. Two parameters will be passed, the first will be the value to be doubled and the second the value to be added to double of the first. Furthermore, instead of showing the result in the console, return it and pass it on in the next function call, for example:

let result;

result = funcao(5, 0); // returning 10
result = funcao(12, result); // returning 34
result = funcao(2, result); // returning 38

Finally, handle this asynchronism again using callback, Promise and async/await.

"End of translation

How to run

• Have node installed
• clone this repository
• In the system console, run node followed by the location/name of the file