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NEW QUESTION # 13
Refer to the code:
01 function execute() {
02 return new Promise((resolve, reject) => reject());
03 }
04 let promise = execute();
05
06 promise
07 .then(() => console.log('Resolved1'))
08 .then(() => console.log('Resolved2'))
09 .then(() => console.log('Resolved3'))
10 .catch(() => console.log('Rejected'))
11 .then(() => console.log('Resolved4'));
What is the result when the Promise in the execute function is rejected?
Answer: B
Explanation:
Comprehensive and Detailed Explanation From Exact Extract JavaScript Knowledge:
execute() returns a Promise that immediately calls reject().
So promise starts in a rejected state.
When a Promise is rejected and you chain .then() calls without rejection handlers, all those .then() callbacks are skipped until a .catch() is encountered:
promise
.then(...) // skipped
.then(...) // skipped
.then(...) // skipped
.catch(...) // executed
.then(...); // executed after catch
Execution:
.then(() => console.log('Resolved1')) is skipped.
.then(() => console.log('Resolved2')) is skipped.
.then(() => console.log('Resolved3')) is skipped.
.catch(() => console.log('Rejected')) runs and logs Rejected.
The .catch() returns a resolved Promise (no explicit return, so undefined), so the next .then() runs:
.then(() => console.log('Resolved4')) logs Resolved4.
Final output:
Rejected
Resolved4
This matches option D.
________________________________________
NEW QUESTION # 14
A Node.js server library uses events and callbacks. The developer wants to log any issues the server has at boot time.
Which code logs an error with an event?
Answer: B
Explanation:
console.log('ERROR', error);
}
Explanation:
Node.js event-based modules use the EventEmitter pattern.
The correct syntax for listening to events is:
emitter.on('eventName', callback)
The server library emits an 'error' event, which must be listened to using .on.
Option analysis:
A: .catch is for Promises, not EventEmitters.
B: .error is not an EventEmitter method.
C: Correct. Listens to the 'error' event.
D: try...catch only captures synchronous errors, not event-based asynchronous errors.
Therefore, the correct answer is option C.
JavaScript Knowledge Reference (text-only)
The EventEmitter API uses on(event, handler) to listen for events.
Errors emitted asynchronously cannot be caught with try...catch.
The 'error' event is standard for Node.js modules to signal operational errors.
NEW QUESTION # 15
Refer to the code below:
let strNumber = '12345';
Which code snippet shows a correct way to convert this string to an integer?
Answer: D
Explanation:
The correct answer is C.
The original option contains a typing error. It should use the existing variable name:
let numberValue = Number(strNumber);
The value of strNumber is a string:
'12345'
Using Number() converts the numeric string into a JavaScript number:
12345
So after execution:
typeof numberValue;
returns:
"number"
Professional review of each option:
Option
Result
Explanation:
A
Incorrect
JavaScript does not have a standard global Integer() conversion function.
B
Incorrect
Strings do not have a standard .toInteger() method.
C
Correct
Number(strNumber) correctly converts '12345' into 12345.
D
Incorrect
This is not valid JavaScript casting syntax.
A commonly used alternative would also be:
let numberValue = parseInt(strNumber, 10);
But from the provided answer choices, the verified answer is C.
NEW QUESTION # 16
Refer to code below:
function Person() {
this.firstName = 'John';
}
Person.prototype ={
Job: x => 'Developer'
};
const myFather = new Person();
const result=myFather.firstName + ' ' + myFather.job();
What is the value of the result after line 10 executes?
Answer: B
NEW QUESTION # 17
A class was written to represent items for purchase in an online store, and a second class representing items that are on sale at a discounted price. The constructor sets the name to the first value passed in. There is a new requirement for a developer to implement a description method that will return a brief description for Item and SaleItem.
01 let regItem = new Item('Scarf', 55);
02 let saleItem = new SaleItem('Shirt', 80, .1);
03 Item.prototype.description = function() { return 'This is a ' + this.name; }
04 console.log(regItem.description());
05 console.log(saleItem.description());
06
07 SaleItem.prototype.description = function() { return 'This is a discounted ' + this.name; } What is the output when executing the code above?
Answer: C
Explanation:
Comprehensive and Detailed
Assuming SaleItem inherits from Item via prototype (e.g. SaleItem.prototype = Object.create(Item.prototype)):
Lines 01-02: create regItem and saleItem.
Line 03: define Item.prototype.description.
Now both regItem and saleItem (via inheritance) have a description method from Item.prototype.
Line 04: regItem.description() → 'This is a Scarf'.
Line 05: saleItem.description() → 'This is a Shirt' (same method, but this.name is 'Shirt').
Line 07: SaleItem.prototype.description = ... overrides description only for SaleItem instances going forward.
If we imagine calling regItem.description() and saleItem.description() again after line 07:
regItem.description() still uses Item.prototype.description → 'This is a Scarf'.
saleItem.description() now uses SaleItem.prototype.description → 'This is a discounted Shirt'.
Those four lines correspond to option B.
________________________________________
NEW QUESTION # 18
......
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