JavaScript-Developer-I無料問題集「Salesforce Certified JavaScript Developer I」

質問 1

Refer to the code below:

What is the output of this function when called with an empty array?

（A）Return 5

（B）Return 0

（C）Return Infinity

（D）Return NaN

正解：A 解答を投票する

質問 2

After user acceptance testing, the developer is asked to change the webpage background based on user's location. This change was implemented and deployed for testing.
The tester reports that the background is not changing, however it works as required when viewing on the developer's computer.
Which two actions will help determine accurate results?
Choose 2 answers

（A）The developer should rework the code.

（B）The tester should disable their browser cache.

（C）The developer should inspect their browser refresh settings.

（D）The tester should dear their browser cache.

正解：C、D 解答を投票する

質問 3

Given the requirement to refactor the code above to JavaScript class format, which class definition is correct?

（A）

（B）

（C）

（D）

正解：B 解答を投票する

質問 4

Teams at Universal Containers (UC) work on multiple JavaScript projects at the same time.
UC is thinking about reusability and how each team can benefit from the work of others.
Going open-source or public is not an option at this time.
Which option is available to UC with npm?

（A）Private registries are not supported by npm, but packages can be installed via git.

（B）Private registries are not supported by npm, but packages can be installed via URL.

（C）Private packages are not supported, but they can use another package manager likeyarn.

（D）Private packages can be scored, andscopes can be associated to a privateregistries.

正解：D 解答を投票する

質問 5

Which two console logs output NaN?
Choose 2 answers | |

（A）console.log(parseInt ' ("two')) ;

（B）console.log(10 / Number('5) ) ;

（C）console.log(10 / 0);

（D）console.loeg(10 / 'five');

正解：A、B 解答を投票する

質問 6

A developer wants to define a function log to be used a few times on a single-file JavaScript script.
01 // Line 1 replacement
02 console.log('"LOG:', logInput);
03 }
Which two options can correctly replaceline 01 and declare the function for use?
Choose 2 answers

（A）const log(loginInput) {

（B）function leg(logInput) {

（C）const log = (logInput) => {

（D）function log = (logInput) {

正解：B、C 解答を投票する

質問 7

bar, awesome is a popular JavaScript module. the versions publish to npm are:

Teams at Universal Containers use this module in a number of projects. A particular project has thepackage, json definition below.

A developer runs this command: npm install.
Which version of bar .awesome is installed?

（A）1.3.5

（B）1.3.1

（C）The command fails, because version 130 is not found

（D）1.4.0

正解：A 解答を投票する

質問 8

Refer to the code below:
let timeFunction =() => {
console.log('Timer called.");
};
let timerId = setTimeout (timedFunction, 1000);
Which statement allows a developer to cancel the scheduled timed function?

（A）clearTimeout(timerId);

（B）removeTimeout(timerId);

（C）clearTimeout(timedFunction);

（D）removeTimeout(timedFunction);

正解：A 解答を投票する

質問 9

Refer to the code below:
Const resolveAfterMilliseconds = (ms) => Promise.resolve (
setTimeout ((=> console.log(ms), ms ));
Const aPromise = await resolveAfterMilliseconds(500);
Const bPromise = await resolveAfterMilliseconds(500);
Await aPromise, wait bPromise;
What is the result of running line 05?

（A）Only aPromise runs.

（B）Neither aPromise or bPromise runs.

（C）aPromise and bPromise run in parallel.

（D）aPromise and bPromise run sequentially.

正解：B 解答を投票する

質問 10

Given the following code:
Let x =('15' + 10)*2;
What is the value of a?

（A）3020

（B）50

（C）35

（D）1520

正解：A 解答を投票する

質問 11

Which two console logs outputs NaN ?
Choose 2 answers

（A）console.log(10/0);

（B）console.log(10/ ''five);

（C）console.log(parseInt('two'));

（D）console.log(10/ Number('5'));

正解：B、C 解答を投票する

質問 12

Given two expressions var1 and var2. What are two valid ways to return the logical AND of the two expressions and ensure it is data type Boolean ?
Choose 2 answers:

（A）var1.toBoolean() && var2toBoolean()

（B）Boolean(var1) && Boolean(var2)

（C）var1 && var2

（D）Boolean(var1 && var2)

正解：B、D 解答を投票する

質問 13

A developer is required to write a function that calculates the sum of elements in an array but is getting undefined every time the code is executed. The developer needs to find what is missing in the code below.
Const sumFunction = arr => {
Return arr.reduce((result, current) => {
//
Result += current;
//
), 10);
);
Which option makes the code work as expected?

（A）Replace line 03 with if(arr.length == 0 ) ( return 0; )

（B）Replace line02 with return arr.map(( result, current) => (

（C）Replace line 05 with return result;

（D）Replace line 04 with result = result +current;

正解：C 解答を投票する

質問 14

Refer to the code declarations below:

Which three expressions return the string JavaScript?
Choose 3 answers

（A）$(str1) $ (str2} ';

（B）Str1.concat (str2);

（C）Concat (str1, str2);

（D）Str1.join (str2);

（E）Str1 + str2;

正解：A、B、E 解答を投票する

質問 15

Refer to the code below:
Const searchTest = 'Yay! Salesforce is amazing!" ;
Let result1 = searchText.search(/sales/i);
Let result 21 = searchText.search(/sales/i);
console.log(result1);
console.log(result2);
After running this code, which result is displayed on the console?

（A）> 5 > 0

（B）> 5 >undefined

（C）> 5 > -1

（D）> true > false

正解：C 解答を投票する

質問 16

A developer is working on an ecommerce website where the delivery date is dynamically calculated based on the current day. The code line below is responsible for this calculation.
Const deliveryDate = new Date ();
Due to changes in the business requirements, the delivery date must now be today's date + 9 days.
Which code meets thisnew requirement?

（A）deliveryDate.setDate(( new Date ( )).getDate () +9);

（B）deliveryDate.setDate( Date.current () + 9);

（C）deliveryDate.date = new Date(+9) ;

（D）deliveryDate.date = Date.current () + 9;

正解：A 解答を投票する

質問 17

Given the following code:
document.body.addEventListener(' click ', (event) => {
if (/* CODE REPLACEMENT HERE */) {
console.log('button clicked!');
)
});
Which replacement for the conditional statement on line 02 allows a developer to correctly determine that a button on page is clicked?

（A）event.target.nodeName == 'BUTTON'

（B）Event.clicked

（C）button.addEventListener('click')

（D）e.nodeTarget ==this

正解：A 解答を投票する

質問 18

Refer to the following code:
function test (val) {
If (val === undefined) {
return 'Undefined values!' ;
}
if (val === null) {
return 'Null value! ';
}
return val;
}
Let x;
test(x);
What is returned by the function call on line 13?

（A）Undefined

（B）'Undefined values!'

（C）'Null value!'

（D）Line 13 throws an error.

正解：B 解答を投票する

質問 19

developer uses the code below to format a date.

After executing, what is the value offormattedDate?

（A）October 05, 2020

（B）November 05, 2020

（C）May 10, 2020

（D）June 10, 2020

正解：D 解答を投票する

質問 20

Refer to the code below:
Function changeValue(obj) {
Obj.value = obj.value/2;
}
Const objA = (value: 10);
Const objB = objA;
changeValue(objB);
Const result = objA.value;
What is the value of result after the code executes?

（A）Undefined

（B）5

（C）10

（D）Nan

正解：B 解答を投票する

JavaScript-Developer-I 無料問題集「Salesforce Certified JavaScript Developer I」

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