JavaScript-Developer-I試験無料問題集（224題）「Salesforce Certified JavaScript Developer I 認定」

出題：1

Refer to the following array:
Let arr1 = [ 1,2, 3, 4, 5 ];

Which two lines of code result in a second array, arr2 being created such that arr2 is not a reference to arr1?

A. Let arr2 = arr1.slice(0, 5);

B. Let arr2 = arr1;

C. Let arr2 = arr1.sort();

D. Let arr2 = Array.from(arr1);

正解：A,D 解答を投票する

出題：2

A developer is creating a simple webpage with a button. When a userclicks this button for the first time, a message is displayed.
The developer wrote the JavaScript code below, but something is missing. The message gets displayed every time a user clicks the button, instead of just the first time.
01 functionlisten(event) {
02 alert ( 'Hey! I am John Doe') ;
03 button.addEventListener ('click', listen);
Which two code lines make this code work as required?
Choose 2 answers

A. On line 02, use event.first to test if it is the first execution.

B. On line 04, useevent.stopPropagation ( ),

C. On line 04, use button.removeEventListener(' click" , listen);

D. On line 06, add an option called once to button.addEventListener().

正解：C,D 解答を投票する

出題：3

Universal Containers recently launched its new landing page to host a crowd-funding campaign. The page uses an external library to display some third-party ads. Once the page is fully loaded, it creates more than 50 new HTML items placed randomly insidethe DOM, like the one in the code below:

All the elements includes the same ad-library-item class, They are hidden by default, and they are randomly displayed while the user navigates through the page.

A. Use the browser console to execute a scriptthat prevents the load event to be fired.

B. Use the browser to execute a script that removes all the element containing the class ad-library-item.

C. Use the DOM inspector to prevent the load eventto be fired.

D. Use the DOM inspector to remove all the elements containing the class ad-library-item.

正解：B 解答を投票する

出題：4

Refer to the following array:
Let arr = [ 1,2, 3, 4, 5];
Which three options result in x evaluating as [3, 4, 5] ?
Choose 3 answers.

A. Let x= arr.filter (( a) => (a<2));

B. Letx= arr.filter((a) => ( return a>2 ));

C. Let x= arr.slice(2);

D. Let x = arr.slice(2,3);

E. Let x= arr.splice(2,3);

正解：B,C,E 解答を投票する

出題：5

Which option is a core Node,js module?

A. Memory

B. Path

C. Ios

D. locate

正解：B 解答を投票する

出題：6

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

A. console.log(parseInt ' ("two')) ;

B. console.loeg(10 / 'five');

C. console.log(10 / 0);

D. console.log(10 / Number('5) ) ;

正解：A,D 解答を投票する

出題：7

Which function should a developer use to repeatedly execute code at a fixed interval ?

A. setTimeout

B. setInteria

C. setIntervel

D. setPeriod

正解：C 解答を投票する

出題：8

A developer copied a JavaScript object:

How does the developer access dan's forstName,lastName? Choose 2 answers

A. dan,name ( )

B. dan,name

C. dan,firstname ( ) + dan, lastName ( )

D. dan, firstName =dan.lastName

正解：A,D 解答を投票する

出題：9

Refer to the code below:
const event = new CustomEvent(
//Missing Code
);
obj.dispatchEvent(event);
A developer needs to dispatch a custom event called update to send information about recordId.
Which two options could a developer insert at the placeholder in line 02 to achieve this?
Choose 2 answers

A. 'Update' , {Details : {recordId : '123abc'}}

B. 'Update' , '123abc'

C. 'Update' , (recordId : '123abc'(

D. { type : 'update', recordId : '123abc' }

正解：A,C 解答を投票する

出題：10

Referto the code below:
new Promise((resolve, reject) => {
const fraction = Math.random();
if( fraction >0.5) reject("fraction > 0.5, " + fraction);
resolve(fraction);
})
.then(() =>console.log("resolved"))
.catch((error) => console.error(error))
.finally(() =>console.log(" when am I called?"));

When does Promise.finally on line 08 get called?

A. When resolved

B. When resolved and settled

C. When rejected

D. When resolved or rejected

正解：D 解答を投票する

出題：11

Refer to code below:
Const objBook = {
Title: 'Javascript',
};
Object.preventExtensions(objBook);
Const newObjBook = objBook;
newObjectBook.author ='Robert';
What are the values of objBook and newObjBook respectively ?

A. {author: "Robert", title: "javaScript}Undefined

B. {author: "Robert", title: "javaScript}{author: "Robert", title: "javaScript}

C. [title: "javaScript"] [title: "javaScript"]

D. {author: "Robert"}{author: "Robert", title: "javaScript}

正解：C 解答を投票する

出題：12

Given code below:
setTimeout (()=> (
console.log(1);
). 0);
console.log(2);
New Promise ((resolve, reject )) = > (
setTimeout(() => (
reject(console.log(3));
). 1000);
)).catch(() => (
console.log(4);
));
console.log(5);
What is logged to the console?

A. 2 5 1 3 4

B. 2 1 4 3 5

C. 1 2 43 5

D. 1 2 5 3 4

正解：A 解答を投票する

出題：13

A developer wants to create an object from a function in the browser using the code below.

What happens due to the lack of the mm keyword on line 02?

A. The m variable is assigned the correct object.

B. The m variable is assigned the correct object but this.name remains undefined.

C. window.name is assigned to 'hello' and the variable = remains undefined.

D. window.m Is assigned the correct object.

正解：C 解答を投票する

出題：14

A developer is wondering whether to use, Promise.then or Promise.catch, especially when a Promise throws an error?
Which two promises are rejected?
Which 2 are correct?

A. New Promise(() => (throw 'cool error here'}).then(null, error => console.error(error)));

B. Promise.reject('cool errorhere').then(error => console.error(error));

C. Promise.reject('cool error here').catch(error => console.error(error));

D. New Promise((resolve, reject) => (throw 'cool error here'}).catch(error =>console.error(error)) ;

正解：C,D 解答を投票する

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