codecademy quiz——JavaScript Promise

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• What is the fulfilled value of Promise.all()?

 A Promise     An object     An array

• What is value of the argument that is passed to the onReject()?

let onFulfill = value => {console.log(value)}; 

let onReject = reason => {console.log(reason)}; 

const promise = new Promise( (resolve, reject) => { 

    if (false) { 

        resolve('success value'); 

    } else { 

        reject(); 

    } 

}); 

 

promise.then(onFulfill, onReject);

 ‘success value’     reason     undefined

• True or False: The .then() method returns a Promise.

 False     True

• How many parameters does a Promise constructor take?

const example = new Promise( ? ? ? );

 2     1     3

• What value is printed to the console?

const asyncHello = new Promise((resolve, reject) => { 

    setTimeout(resolve, 1000, 'Hello!'); 

}); 

 

console.log(typeof asyncHello);

 Promise     Object     Number     String

• Which one of the following is NOT a state that a Promise resolves to?

 Rejected     Fulfilled     Undefined     Pending

• What state will this promise be in after 0 seconds?

const examplePromise = () => { 

    return new Promise((resolve, reject) => { 

        if (true) { 

            setTimeout( () => resolve('success'), 3000); 

        } else { 

            setTimeout( () => resolve('failed'), 5000); 

        } 

    }); 

};

 Fulfilled     Rejected     Pending

• What will be printed to the console after running the code provided?

let link = state => { 

    return new Promise(function(resolve, reject) { 

        if (state) { 

            resolve('success'); 

        } else { 

            reject('error'); 

        } 

    }); 

} 

 

let promiseChain = link(true); 

 

promiseChain 

.then( data => {

    console.log(data + " 1"); 

    return link(true); 

})

.then( data => { 

    console.log(data+ " 2"); 

    return link(true); 

});

Your Answer: 

 

 

 

• Which of the executor function’s parameter is called if the asynchronous task completes successfully?

const example = new Promise( (function1, function2) => { 

    . . . 

});

 function1     function2     function1 or function2

• True or False: promise1 and promise2 both produce the same output.

const examplePromise1 = new Promise((resolve, reject) => {

    reject('Uh-oh!') 

}); 

 

const examplePromise2 = new Promise((resolve, reject) => { 

    reject('Uh-oh!') 

}); 

 

const onFulfill = value => {

    console.log(value)

}; 

 

const onReject = reason => {

    console.log(reason)

}; 

 

const promise1 = examplePromise1.then(onFulfill, onReject); 

const promise2 = examplePromise2.then(onFulfill).catch(onReject);

 False     True