Most Recent Salesforce JS-Dev-101 Exam Dumps

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Comprehensive and Detailed Explanation From Exact Extract JavaScript Knowledge

The syntax:

import printPrice from 'module';

means the module must export its function as a default export:

export default function printPrice() { ... }

Why the others are wrong:

Named exports require curly braces:

import { printPrice } from 'module';

''all export'' and ''multi export'' are not JavaScript terms.

Therefore, printPrice must be the default export.

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JavaScript Knowledge Reference (text-only)

Default imports use: import name from 'module'.

Named imports require braces: import { name } from 'module'.

Comprehensive and Detailed Explanation From Exact Extract JavaScript knowledge:

First, recall the fizzbuzz rules:

If n divisible by 3 and not by 5 return 'fizz'.

If n divisible by 5 and not by 3 return 'buzz'.

If n divisible by both 3 and 5 return 'fizzbuzz'.

Otherwise return '' (empty string).

Evaluate each test:

Option A:

let res = fizzbuzz(true);

console.assert(res === '');

In JavaScript, when using arithmetic operations with true, it is coerced to the number 1. A typical implementation of fizzbuzz would treat the argument as a number and compute:

true % 3 1 % 3 1

true % 5 1 % 5 1

So true is effectively treated as 1, which is divisible by neither 3 nor 5. The function should return ''. The assertion res === '' will pass.

This test covers the scenario ''neither divisible by 3 nor 5''.

Option B:

let res = fizzbuzz(3);

console.assert(res === '');

3 is divisible by 3 but not by 5.

According to fizzbuzz rules, fizzbuzz(3) should return 'fizz'.

This test expects '', so it is incorrect; the assertion would fail in a correct implementation.

Option C:

let res = fizzbuzz(5);

console.assert(res === 'fizz');

5 is divisible by 5 but not by 3.

According to fizzbuzz rules, fizzbuzz(5) should return 'buzz'.

This test expects 'fizz', so it is incorrect.

Option D:

let res = fizzbuzz(15);

console.assert(res === 'fizzbuzz');

15 is divisible by both 3 and 5.

According to fizzbuzz rules, fizzbuzz(15) should return 'fizzbuzz'.

This assertion correctly matches the expected result, so it is a proper test case.

Thus, the two test cases that correctly test valid fizzbuzz behavior are:

Study Guide / Concept Reference (no links):

Modulo operator (%) for divisibility checks

Truthy/number coercion of boolean true in arithmetic (Number(true) === 1)

Designing unit tests with console.assert

Typical fizzbuzz logic structure and expected outputs

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Comprehensive and Detailed

Errors thrown inside setTimeout callbacks occur asynchronously, in a different tick of the event loop. A try...catch around setTimeout itself (as in D) cannot catch errors thrown later in the scheduled callback.

To catch errors from countSheep() when it's called asynchronously, the try...catch must wrap the call inside the timeout callback:

setTimeout(function() {

try {

countSheep();

} catch (e) {

handleError(e);

}

}, 1000);

B uses finally incorrectly and references e out of scope.

C is not valid JavaScript syntax.

D's catch can only handle synchronous errors thrown before setTimeout returns, not those thrown inside the callback.

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Comprehensive and Detailed Explanation From Exact Extract JavaScript Knowledge:

Execution order:

Top-level code runs synchronously:

Line 14: console.log(4); logs 4.

Line 15: callDelay(); is called.

Inside callDelay:

Line 9: console.log(2); logs 2.

Line 10: await delay(1000);:

Calls delay(1000).

Inside delay(1000):

Line 3: console.log(1); logs 1.

Line 4: setTimeout(resolve, delay); schedules resolve in 1000 ms.

delay returns a pending Promise. await pauses callDelay here and returns control to the event loop.

Back to top-level:

Line 16: console.log(5); logs 5.

So synchronous log sequence is: 4, 2, 1, 5.

After ~1000 ms:

The setTimeout in delay resolves the Promise.

The await in callDelay resumes.

Line 11: console.log(3); logs 3.

Final log order: 4 2 1 5 3.

Both A and B show the same sequence; one must be chosen, so A is correct.

Concepts: async/await flow, Promise resolution timing, event loop, and ordering of synchronous vs timer callbacks.

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