合格できるSalesforce JavaScript-Developer-IのPDF問題集！最近更新された149問あります
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質問 # 52
developer is trying to convince management that their team will benefit from using
Node.js for a backend server that they are going to create. The server will be a web server that
handles API requests from a website that the team has already built using HTML, CSS, and
JavaScript.
Which three benefits of Node.js can the developer use to persuade their manager?
Choose 3 answers:
- A. Executes server-side JavaScript code to avoid learning a new language.
- B. Performs a static analysis on code before execution to look for runtime errors.
- C. I nstalls with its own package manager to install and manage third-party libraries.
- D. User non blocking functionality for performant request handling .
- E. Ensures stability with one major release every few years.
正解：B、C、D
質問 # 53
Which option is true about the strict mode in imported modules?
- A. Add the statement use non-strict; before any other statements in the module to enable notstrict mode.
- B. Add the statement use strict = false; before any other statements in the module to enable notstrict mode.
- C. A developer can only reference notStrict() functions from the imported module.
- D. Imported modules are in strict mode whether you declare them as such or not.
正解：D
解説：
In JavaScript, ES modules (files imported using import / export) have special semantics:
* All code inside a module is automatically executed in strict mode .
* This is specified by the ECMAScript standard and does not require the explicit " use strict " ; directive.
Effects:
* You do not need to write " use strict " ; at the top of a module file.
* You cannot turn strict mode off for module code.
* All module top-level code is treated as strict.
Now evaluate each option:
Option A:
Add the statement use non-strict; before any other statements in the module to enable notstrict mode.
* There is no use non-strict; directive in JavaScript.
* The only directive recognized by engines is " use strict " ;.
* You cannot explicitly enable a "non-strict" mode with such a string.
Option B:
Imported modules are in strict mode whether you declare them as such or not.
* This matches the language specification.
* ES modules are always in strict mode, automatically.
* This is true.
Option C:
Add the statement use strict = false; before any other statements in the module to enable notstrict mode.
* use strict = false; is not a directive; it is parsed as a normal expression, and does not affect strict mode.
* There is no supported way to disable strict mode in modules.
Option D:
A developer can only reference notStrict() functions from the imported module.
* There is no special notStrict() restriction in modules.
* Functions exported/imported in modules are simply subject to strict mode rules like the rest of the module's code.
Therefore, the only correct statement is:
The answer: B
Study Guide / Concept References (no links):
* ES modules (import / export)
* Automatic strict mode in modules
* " use strict " ; directive for scripts vs modules
* Inability to disable strict mode in ES module code
質問 # 54
A developer executes:
document.cookie;
document.cookie = ' key=John Smith ' ;
What is the behavior?
- A. Cookies are read and the key value is set, the remaining cookies are unaffected.
- B. Cookies are not read because line 01 should be document.cookies, but the key value is set and all cookies are wiped.
- C. Cookies are read and the key value is set, and all cookies are wiped.
- D. Cookies are read, but the key value is not set because the value is not URL encoded.
正解：A
質問 # 55
Refer to the code below:
Async funct on functionUnderTest(isOK) {
If (isOK) return 'OK' ;
Throw new Error('not OK');
)
Which assertion accuretely tests the above code?
- A. Console.assert (await functionUnderTest(true), 'OK')
- B. Console.assert (await functionUnderTest(true), ' not OK ')
- C. Console.assert (await functionUnderTest(true), ' not OK ')
- D. Console.assert (await functionUnderTest(true), ' OK ')
正解：A
質問 # 56
A developer has an is Dog function that takes one argument cat. They want to schedule the function to run every minute.
What is the correct syntax for scheduling this function?
- A. setInterval(isDog, 60000,'cat');
正解：A
質問 # 57
Refer to the following code that performs a basic mathematical operation on a provided input:
function calculate(num) {
Return (num +10) / 3;
}
How should line 02 be written to ensure that x evaluates to 6 in the line below?
Let x = calculate (8);
- A. Return Number((num +10) /3 );
- B. Return (Number (num +10 ) / 3;
- C. Return Integer(num +10) /3;
- D. Return Number(num + 10) / 3;
正解：B
質問 # 58
A developer wants to use a module named universalContainerLib and then call functions from it.
How should a developer import every function from the module and then call the functions foo and bar?
- A. import (foo,bar) from '/path/universalContainerLib.js''
foo ( ) ;
bar ( ) ; - B. import + from '/path/universalContainerLib.js''
universalContainersLib.foo( ) ;
universalContainersLib bar ( ) : - C. import all from '/path/universalContainerLib.js''
universalContainersLib.foo( ) ;
universalContainersLib bar ( ) : - D. import - as lib from '/path/universalContainerLib.js''
lib.foo( ) ;
lib. bar ( ) ;
正解：D
質問 # 59
Given the following code:
Which replacement for the conditional statement on line 02 allows a developer to correctly determine that a button on the page is clicked?
- A. Event, clicked
- B. button.addEventListener ( 'click')
- C. Event,target.nodename == 'BUTTON"
- D. o.nodeTarget == this
正解：C
質問 # 60
Consider type coercion, what does the following expression evaluate to?
True + 3 + '100' + null
- A. 0
- B. '4100null'
- C. 1
- D. '3100null'
正解：B
質問 # 61
Refer to the code below:
function changeValue(param) {
Param =5;
}
Let a =10;
Let b =5;
changeValue(b);
Const result = a+ " - "+ b;
What is the value of result when code executes?
- A. 5 - 10
- B. 5 -5
- C. 10 -10
- D. 10 - 5
正解：C
質問 # 62
Given the code below:
Function myFunction(){
A =5;
Var b =1;
}
myFunction();
console.log(a);
console.log(b);
What is the expected output?
- A. Line 08 outputs the variable, but line 09 throws an error.
- B. Both lines 08 and 09 are executed, but values outputted are undefined.
- C. Both lines 08 and 09 are executed, and the variables are outputted.
- D. Line 08 thrones an error, therefore line 09 is never executed.
正解：A
質問 # 63
Refer to the code below:
Considering that JavaScript is single-threaded, what is the output of line 08 after the code executes?
- A. 0
- B. 1
- C. 2
- D. 3
正解：B
質問 # 64
Refer to the code below:
Const myFunction = arr => {
Return arr.reduce((result, current) =>{
Return result = current;
}, 10};
}
What is the output of this function when called with an empty array ?
- A. Returns NaN
- B. Throws an error
- C. Returns 10
- D. Returns 0
正解：C
質問 # 65
Given the following code:
What will be the first four numbers logged?
- A. 0112
- B. 0012
- C. 0122
- D. 0123
正解：A
質問 # 66
A developer initiates a server with the file server.js and adds dependencies in the source code ' s package.json that are required to run the server.
Which command should the developer run to start the server locally?
- A. node start
- B. npm start
- C. npm start server.js
- D. start server.js
正解：B
解説：
Comprehensive and Detailed Explanation From JavaScript/Node.js Knowledge:
In a Node.js project that uses package.json, you typically define a " start " script:
{
" scripts " : {
" start " : " node server.js "
}
}
Then you start the app with:
npm start
npm start:
* Looks up the " start " script in package.json.
* Runs the command defined there (commonly node server.js).
* This is the standard way to start a Node.js app with npm-managed dependencies.
Why others are incorrect:
* A. node start
* Tries to run a file named start with Node; does not use package.json scripts.
* C. npm start server.js
* npm start does not take the script filename as an argument in this way; it just runs the start script as defined.
* D. start server.js
* Not an npm or node command; on some shells it just tries to "start" a process but is not the standard Node/npm workflow.
Relevant concepts: package.json, npm scripts, npm start, Node entry file execution.
質問 # 67
Refer tothe code below:
What is the value of result after line 10 executes?
- A. undefined Developer
- B. Error: myFather.job is not a function
- C. John undefined
- D. John Developer
正解：D
質問 # 68
At Universal Containers, every team has its own way of copying JavaScript objects. The code snippet shows an implementation from one team:
What is the output of the code execution?
- A. Hello John Doe
- B. TypeError: Assignment to constant variable
- C. Hello Dan Doe
- D. TypeError: dan.name is not a function
正解：D
質問 # 69
Value of:
true + 3 + ' 100 ' + null
- A. " 4100null "
- B. " 2200null "
- C. " 4100 "
- D. 0
正解：A
解説：
The correct answer is A .
JavaScript evaluates the expression from left to right:
true + 3 + ' 100 ' + null
Step 1:
true + 3
In numeric addition, true is converted to:
1
So:
true + 3
becomes:
1 + 3
Result:
4
Step 2:
4 + ' 100 '
Because one operand is a string, JavaScript performs string concatenation instead of numeric addition.
So:
4 + ' 100 '
becomes:
" 4100 "
Step 3:
" 4100 " + null
Again, because one operand is already a string, JavaScript converts null into the string:
" null "
So the final result is:
" 4100null "
Execution summary:
true + 3 + ' 100 ' + null
// 1 + 3 + ' 100 ' + null
// 4 + ' 100 ' + null
// " 4100 " + null
// " 4100null "
Therefore, the verified answer is A .
質問 # 70
Refer to code below:
console.log(0);
setTimeout(() => (
console.log(1);
});
console.log(2);
setTimeout(() => {
console.log(3);
), 0);
console.log(4);
In which sequence will the numbers be logged?
- A. 01234
- B. 02413
- C. 02431
- D. 0
正解：B
質問 # 71
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Salesforce JavaScript-Developer-I認定試験を受けるには、候補者は、データ型、制御構造、機能などの基本的なJavaScriptの概念を確実に理解する必要があります。また、Apex、Visualforce、Lightningコンポーネントフレームワークなど、Salesforceプラットフォームにも精通している必要があります。さらに、候補者は、HTML、CSS、jQueryやAngularjsなどのJavaScriptフレームワークなどのWeb開発技術の経験を持つ必要があります。
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問題集お試しセットJavaScript-Developer-Iテストエンジン問題集トレーニングには149問あります：https://drive.google.com/open?id=1EJvZw0QScx1_KnWYDjW-rX37ohogBteM