Salesforce Javascript-Developer-I Exam Dumps

Salesforce Certified JavaScript Developer (JS-Dev-101)

698 Reviews

Exam Code	Javascript-Developer-I
Exam Name	Salesforce Certified JavaScript Developer (JS-Dev-101)
Questions	219 Questions Answers With Explanation
Update Date	04, 29, 2026
Price	Was : $90 Today : $50 Was : $108 Today : $60 Was : $126 Today : $70

Add To Cart

Demo Questions

Question # 1

Refer to the code below:01 let car1 = new promise((_, reject) =>02 setTimeout(reject, 2000, “Car 1 crashed in”));03 let car2 = new Promise(resolve => setTimeout(resolve, 1500, “Car 2completed”));04 let car3 = new Promise(resolve => setTimeout (resolve, 3000, “Car 3Completed”));05 Promise.race([car1, car2, car3])06 .then(value => (07 let result = $(value) the race. `;08 ))09 .catch( arr => (10 console.log(“Race is cancelled.”, err);11 ));What is the value of result when Promise.race executes?

A. Car 3 completed the race.
B. Car 1 crashed in the race.
C. Car 2 completed the race.
D. Race is cancelled.

Show Answer

Question # 2

Why would a developer specify a package.jason as a developed forge instead of adependency ?

A. It is required by the application in production.
B. It is only needed for local development and testing.
C. Other requiredpackages depend on it for development.
D. It should be bundled when the package is published.

Show Answer

Question # 3

A test has a dependency on database. query. During the test, the dependency is replacedwith an object called database with the method,Calculator query, that returns an array. The developer does notneed to verify how manytimes the method has been called.Which two test approaches describe the requirement?Choose 2 answers

A. White box
B. Stubbing
C. Black box
D. Substitution

Show Answer

Question # 4

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. Themessage 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().

Show Answer

Question # 5

Given the following code:Let x =null;console.log(typeof x);What is the output of the line 02?

A. “Null”
B. “X”
C. “Object”
D. “undefined”

Show Answer

Question # 6

Which statement accurately describes an aspect of promises?

A. Arguments for the callback function passed to .then() are optional.
B. In a.then() function, returning results is not necessary since callbacks will catch theresult of a previous promise.
C. .then() cannot be added after a catch.
D. .then() manipulates and returns the original promise.

Show Answer

Question # 7

Refer to the code below?LetsearchString = ‘ look for this ’;Which two options remove the whitespace from the beginning of searchString?Choose 2 answers

A. searchString.trimEnd();
B. searchString.trimStart();
C. trimStart(searchString);
D. searchString.replace(/*\s\s*/, ‘’);

Show Answer

Question # 8

developer wants to use a module nameduniversalContainersLib and them call functionsfrom it.How should a developer import every function from the module and then call the fuctionsfooand bar ?

A. import * ad lib from ‘/path/universalContainersLib.js’;lib.foo();lib.bar();
B. import (foo, bar) from ‘/path/universalContainersLib.js’;foo();bar();
C. import all from ‘/path/universalContaineraLib.js’;universalContainersLib.foo();universalContainersLib.bar();
D. import * from ‘/path/universalContaineraLib.js’;universalContainersLib.foo();universalContainersLib.bar();

Show Answer

Question # 9

Which statement phrases successfully?

A. JSON.parse ( ‘ foo ’ );
B. JSON.parse ( “ foo ” );
C. JSON.parse( “ ‘ foo ’ ” );
D. JSON.parse(‘ “ foo ” ’);

Show Answer

Question # 10

Which two console logs outputs NaN?Choose 2 answers

A. console.log(10/ Number(‘5’));
B. console.log(parseInt(‘two’));
C. console.log(10/ ‘’five);
D. console.log(10/0);

Show Answer

Question # 11

Which two console logs outputs NaN?Choose 2 answers

A. console.log(10/ Number(‘5’));
B. console.log(parseInt(‘two’));
C. console.log(10/ ‘’five);
D. console.log(10/0);

Show Answer

Question # 12

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 enablenot-strict mode.
B. You can only reference notStrict() functions from the imported module.
C. Imported modules are in strict mode whether you declare them as such or not.
D. Add the statement use strict =false; before any other statements in the module to enablenot- strict mode.

Show Answer

Question # 13

Universal Containers (UC) notices that its application that allows users to search foraccounts makes a network request each time a key is pressed. This results in too manyrequests for the server to handle. Address this problem, UCdecides to implement a debounce function on string changehandler.What are three key steps to implement this debounce function?Choose 3 answers:

A. If there is an existing setTimeout and the search string change, allow the existingsetTimeout to finish,and do not enqueue a new setTimeout.
B. When the search string changes, enqueue the request within a setTimeout.
C. Ensure that the network request has the property debounce set to true.
D. If there is an existing setTimeout and the search string changes,cancel the existingsetTimeout using the persisted timerId and replace it with a new setTimeout.
E. Store the timeId of the setTimeout last enqueued by the search string change handle.

Show Answer

Question # 14

A developer has a web server running with Node.js. The command to start the web serveris node server.js. The web server started havinglatency issues. Instead of a one second turnaround for web requests, the developer nowsees a five second turnaround.Which command can the web developer run to see what the module is doing during thelatency period?

A. NODE_DEBUG=true node server.js
B. DEBUG=http, https node server.js
C. NODE_DEBUG=http,https node server.js
D. DEBUG=true node server.js

Show Answer

Question # 15

GIven a value, which three options can a developer use to detect if the value is NaN?Choose 3 answers !

A. value == NaN
B. Object.is(value, NaN)
C. value === Number.NaN
D. value ! == value
E. Number.isNaN(value)

Show Answer

Question # 16

Consider type coercion, what does the following expression evaluate to?True + 3 + ‘100’ + null

A. 104
B. 4100
C. ‘3100null’
D. ‘4100null’

Show Answer

Question # 17

Refer to the code below:01 const exec = (item, delay) =>{02 newPromise(resolve => setTimeout( () => resolve(item), delay)),03 async function runParallel() {04 Const (result1, result2, result3) = await Promise.all{05 [exec (‘x’, ‘100’) , exec(‘y’, 500), exec(‘z’, ‘100’)]06 );07 return `parallel is done: $(result1)$(result2)$(result3)`;08 }}}Which two statements correctly execute the runParallel () function?Choose 2 answers

A. Async runParallel () .then(data);
B. runParallel ( ). done(function(data){ return data; });
C. runParallel () .then(data);
D. runParallel () .then(function(data) return data

Show Answer

Question # 18

Which code statement correctly retrieves and returns an object from localStorage?

A. const retrieveFromLocalStorage = () =>{return JSON.stringify(window.localStorage.getItem(storageKey));}
B. const retrieveFromLocalStorage = (storageKey) =>{return window.localStorage.getItem(storageKey);}
C. const retrieveFromLocalStorage = (storageKey) =>{returnJSON.parse(window.localStorage.getItem(storageKey));}
D. const retrieveFromLocalStorage = (storageKey) =>{return window.localStorage[storageKey];}

Show Answer

Question # 19

Refer to following code block:Let array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,];Let output =0;For (let num of array){if (output >0){Break;}if(num % 2 == 0){Continue;}Output +=num;What is the value of output after the code executes?

A. 16
B. 36
C. 11
D. 25

Show Answer

Question # 20

Refer to the code below:Let str = ‘javascript’;Str[0] = ‘J’;Str[4] = ’S’;After changing the string index values, the value of str is ‘javascript’. What is the reasonfor this value:

A. Non-primitive values are mutable.
B. Non-primitive values are immutable.
C. Primitive values are mutable.
D. Primitive values are immutable.

Show Answer

Question # 21

In which situation should a developer include a try .. catch block around their function call ?

A. The function has an error that shouldnot be silenced.
B. The function results in an out of memory issue.
C. The function might raise a runtime error that needs to be handled.
D. The function contains scheduled code.

Show Answer

Question # 22

A developer has code that calculates a restaurant bill, but generates incorrectanswerswhile testing the code:function calculateBill ( items ) { let total = 0;total += findSubTotal(items);total += addTax(total);total += addTip(total);return total;}Which option allows the developer to step into each function execution within calculateBill?

A. Using the debugger command on line 05.
B. Using the debugger command on line 03
C. Calling the console.trace (total) method on line 03.
D. Wrapping findSubtotal in a console.log() method.

Show Answer

Question # 23

Refer to code below:function Person() {this.firstName = ’John’;}Person.prototype ={Job: x => ‘Developer’};const myFather = new Person();const result =myFather.firstName + ‘ ‘ + myFather.job();What is the value of the result after line 10 executes?

A. Error: myFather.job is not a function
B. Undefined Developer
C. John undefined
D. John Developer

Show Answer

Question # 24

Refer to the code below:for(let number =2 ; number <= 5 ; number += 1 ) {// insert code statement here}Thedeveloper needs to insert a code statement in the location shown. The codestatement has these requirements:1. Does require an import2. Logs an error when the boolean statement evaluates to false3. Works in both the browser and Node.jsWhich meet the requirements?

A. assert (number % 2 === 0);
B. console.error(number % 2 === 0);
C. console.debug(number % 2 === 0);
D. console.assert(number % 2 === 0);

Show Answer

Question # 25

developer has a web server running with Node.js. The command to start the webserver is node server,js. The web server started having latency issues. Instead of a onesecondturn around for web requests, the developer now sees a five second turnaround,Which command can the web developer run to see what the module is doing during thelatency period?

A. DEBUG = http, https node server.js
B. NODE_DEBUG =http, https node server.js
C. DEBUG =true node server.js
D. NODE_DEBUG =true node server.js

Show Answer