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Fast2test에서는 전문Salesforce JS-Dev-101인증시험을 겨냥한 덤프 즉 문제와 답을 제공합니다.여러분이 처음Salesforce JS-Dev-101인증시험준비라면 아주 좋은 덤프입니다. Fast2test에서 제공되는 덤프는 모두 실제시험과 아주 유사한 덤프들입니다.Salesforce JS-Dev-101인증시험패스는 보장합니다. 만약 떨어지셨다면 우리는 덤프비용전액을 환불해드립니다.
질문 # 66
Given the following code:
let x = ('15' + 10) * 2;
What is the value of x?
정답：D
설명：
Comprehensive and Detailed
Evaluate step by step:
'15' + 10
+ with a string operand performs string concatenation.
10 is coerced to '10'.
Result: '1510'.
'1510' * 2
* always performs numeric multiplication.
'1510' is converted to the number 1510.
1510 * 2 = 3020.
So x is 3020.
질문 # 67
Given the JavaScript below:
01 function filterDOM(searchString){
02 const parsedSearchString = searchString && searchString.toLowerCase();
03 document.querySelectorAll('.account').forEach(account => {
04 const accountName = account.innerHTML.toLowerCase();
05 account.style.display = accountName.includes(parsedSearchString) ? /* Insert code here */;
06 });
07 }
Which code should replace the placeholder comment on line 05 to hide accounts that do not match the search string?
정답：A
설명：
We have a ternary:
account.style.display = accountName.includes(parsedSearchString)
? /* if true */
: /* if false */;
Requirement:
If the account matches the search string → show it.
If it does not match → hide it.
For display:
Show: 'block' (or similar visible value).
Hide: 'none'.
So we want:
account.style.display = accountName.includes(parsedSearchString)
? 'block'
: 'none';
That corresponds to option A.
Why others are wrong:
B, C use values suitable for visibility, not display.
D ('none' : 'block') inverts the logic, hiding matches and showing non-matches.
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질문 # 68
Given two expressions, `exp1` and `exp2`, which two valid ways to return the logical AND of the two expressions and ensure it is a boolean?
정답：B,D
질문 # 69
A developer creates a simple webpage with an input field. When a user enters text and clicks the button, the actual value must be displayed in the console:
HTML:
<input type="text" value="Hello" name="input">
<button type="button">Display</button>
JavaScript:
01 const button = document.querySelector('button');
02 button.addEventListener('click', () => {
03 const input = document.querySelector('input');
04 console.log(input.getAttribute('value'));
05 });
When the user clicks the button, the output is always "Hello".
What needs to be done to make this code work as expected?
정답：C
설명：
________________________________________
Comprehensive and Detailed Explanation From Exact Extract JavaScript Knowledge getAttribute('value') This returns the initial HTML attribute, not the live, updated value.
Even if the user edits the text, the value attribute remains "Hello" because HTML attributes do not update dynamically.
Input elements have a property value that always reflects the live current text inside the field.
So:
input.value
returns the user-entered value.
Therefore, line 04 must use the property, not the attribute:
console.log(input.value);
This ensures the updated input value is displayed.
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JavaScript knowledge references (text-only)
HTML attributes are static and retrieved using getAttribute().
DOM element properties (like value) represent the current live state.
Input value changes update the .value property, not the attribute.
질문 # 70
Refer to the code below:
let inArray = [ [1, 2], [3, 4, 5] ];
Which two statements result in the array [1, 2, 3, 4, 5]?
(With corrected typing errors: usArray → inArray, .. → ....)
정답：A,D
설명：
Comprehensive and Detailed Explanation From Exact Extract JavaScript knowledge:
We start with the array:
let inArray = [ [1, 2], [3, 4, 5] ];
This is an array of two inner arrays:
First element: [1, 2]
Second element: [3, 4, 5]
The desired result is to transform this into a single, flat array:
[1, 2, 3, 4, 5]
This is accomplished by using Array.prototype.concat to concatenate the inner arrays into one new array, optionally combined with the spread syntax (...) or Function.prototype.apply.
Option A: [].concat(...inArray);
Relevant concepts:
Spread syntax (...inArray) expands an iterable into separate arguments.
Array.prototype.concat joins arrays or values into a new array. When you pass arrays as arguments to concat, it flattens them one level into the result.
Step-by-step behavior:
inArray is [ [1, 2], [3, 4, 5] ].
...inArray expands into [1, 2] and [3, 4, 5] as separate arguments.
So [].concat(...inArray) is equivalent to:
[].concat([1, 2], [3, 4, 5]);
concat processes each argument:
For [1, 2], it adds 1 and 2 into the result array.
For [3, 4, 5], it adds 3, 4, and 5 into the result array.
The final outcome is:
[1, 2, 3, 4, 5]
Therefore, Option A correctly produces the desired array.
Option B: [].concat.apply(inArray, []);
Corrected name from usArray to inArray.
Relevant concepts:
Function.prototype.apply(fnThis, argsArray) invokes a function with a specific this value and a list of arguments passed as an array.
Here:
thisArg is inArray.
argsArray is [] (no actual arguments passed).
So the call:
[].concat.apply(inArray, []);
is equivalent to:
Array.prototype.concat.apply(inArray, []);
// i.e. inArray.concat();
Since there are no extra arguments, inArray.concat() simply returns a shallow copy of inArray:
[ [1, 2], [3, 4, 5] ]
This remains an array of arrays and is not flattened into [1, 2, 3, 4, 5]. Therefore, Option B does not produce the required result.
Option C: [].concat::...inArray();
Corrected name from usArray to inArray and .. to ....
This expression uses syntax that is not part of standard JavaScript:
:: (double colon) was proposed in early drafts as a bind operator but is not part of the official ECMAScript standard.
The combination concat::...inArray() is invalid in normal JavaScript engines and cannot be used as a valid way to flatten arrays.
In addition, inArray() would imply calling inArray as a function, but it is an array, which would cause a runtime error.
Hence, Option C is syntactically or semantically invalid in standard JavaScript and does not provide the required result [1, 2, 3, 4, 5].
Option D: [].concat.apply({}, inArray);
Corrected name from usArray to inArray.
Relevant concepts:
Again, Function.prototype.apply is used to call concat with a specific this value and arguments provided as an array.
concat treats its this value as an array-like object but ultimately returns a new array containing concatenated elements.
In this expression:
[].concat.apply({}, inArray);
thisArg is {} (an empty object).
argsArray is inArray, which is [ [1, 2], [3, 4, 5] ].
Using apply, this is interpreted as calling concat like:
Array.prototype.concat.call({}, [1, 2], [3, 4, 5]);
concat then:
Starts from the array-like this (here {} is treated as an empty base).
Takes the first argument [1, 2] and appends its elements 1 and 2 to the result.
Takes the second argument [3, 4, 5] and appends its elements 3, 4, and 5 to the result.
The resulting new array is:
[1, 2, 3, 4, 5]
Therefore, Option D also correctly produces the required array.
Final evaluation of all options:
Option A: Uses spread syntax with concat and correctly flattens one level: [1, 2, 3, 4, 5].
Option B: Equivalent to inArray.concat(), leaving it as [[1, 2], [3, 4, 5]]. Does not flatten the structure.
Option C: Uses non-standard and invalid syntax; not a valid or correct JavaScript solution.
Option D: Uses apply with concat, passing the inner arrays as arguments and flattening one level to [1, 2, 3, 4, 5].
Thus, the two correct statements are:
Reference of JavaScript knowledge documents or Study Guide (concept names only):
Array.prototype.concat (concatenating and one-level flattening behavior) Spread syntax for arrays (...array) Function.prototype.apply (calling a function with a given this value and arguments list) Array flattening by one level using concat with array arguments Distinction between nested arrays and flat arrays in JavaScript
질문 # 71
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우리Fast2test 는 많은IT전문가들로 구성되었습니다. 우리의 문제와 답들은 모두 엘리트한 전문가들이 만들어낸 만큼 시험문제의 적중률은 아주 높습니다. 거이 100%의 정확도를 자랑하고 있습니다. 아마 많은 유사한 사이트들도 많습니다. 이러한 사이트에서 학습가이드와 온라인서비스도 지원되고 있습니다만 우리Fast2test는 이미 이러한 사이트를 뛰어넘은 실력으로 업계에서는 우리만의 이미지를 지키고 있습니다. 우리는 정확한 문제와답만 제공하고 또한 그 어느 사이트보다도 빠른 업데이트로 여러분의 인증시험을 안전하게 패스하도록합니다.Salesforce JS-Dev-101인증시험을 응시하려는 분들은 저희 문제와 답으로 안심하시고 자신 있게 응시하시면 됩니다. 우리Fast2test 는 여러분이 100%Salesforce JS-Dev-101인증시험을 패스할 수 있다는 것을 보장합니다.
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