Promises & Async/Await exercises

Exercise 1

        
Function declaration:
        
          const promise1 = new Promise((res) => {
            setTimeout(() => {
              res('Hello, world')
            }, 2000)
          })
        
      

Exercise 2

        
Function declaration:
        
          promise1.then((res) => console.log(res))
        
      

Exercise 3

        
Function declaration:
        
          const sayHello = async (input) => {
            return new Promise((res, err) => {
              if (input === 'Hello') {
                setTimeout(() => {
                  res('Hello, world')
                }, 2000)
                return
              }
              err('The input is not "Hello"')
            })
          }
        
      

        
Code for its execution:
        
          sayHello('Hola')
            .then((res) => console.log(res))
            .catch((err) => console.log(err))

          sayHello('Hello')
            .then((res) => console.log(res))
            .catch((err) => console.log(err))          
        
      

Exercise 4

        
Function declaration:
        
          const waitForResult = async () => {
            const result = await promise1
            return result
          }
        
      

        
Code for its execution:
        
          waitForResult().then((res) => console.log(res))
        
      

Exercise 5

        
Function declaration:
        
          try {
            waitForResult().then((res) => console.log(res))
          } catch (error) {
            console.log(error)
          }
        
      

Exercise 6

        
Functios declaration:
               
          const promise6a = new Promise((res) => {
            setTimeout(() => {
              res('I have waited for 2 seconds...')
            }, 2000)
          })

          const promise6b = new Promise((res) => {
            setTimeout(() => {
              res('Well, I have waited for 3...')
            }, 3000)
          })
        
      

        
Code for its execution:
        
          Promise.all([promise6a, promise6b]).then((results) => {
            console.log(results)
          })