Salesforce Salesforce Certifications JAVASCRIPT-DEVELOPER-I Questions & Answers

• Question 201:

  A developer has two ways to write a function:

  Option A:

  function Monster(){

  this.growl = ()=>{

  console.log('Grr!');

  }

  }

  Option B:

  function Monster(){};

  Monster.prototype.growl = ()=>{

  console.log('Grr!');

  }

  After deciding on an option, the developercreates 1000 monster objects.

  How many growl methods are created with Option A and Option B?

  A. 1000 for Option A, 1 for Option B

  B. 1 methods for both

  C. 1000 for both

  D. 1 for Option A, 1000 for Option B

  Correct Answer: B

• Question 202:

  Refer to the code declarations below:

  

  Whichthree expressions return the string JavaScript? Choose 3 answers

  A. Str1.join (str2);

  B. Str1.concat (str2);

  C. Concat (str1, str2);

  D. $(str1) $ (str2} `;

  E. Str1 + str2;

  Correct Answer: BDE

• Question 203:

  Refer to the code below

  let inArray = [[1,2],[3,4,5]];

  which two statements results in the array [1,2,3,4,5]?

  choose 2 answer

  A. [ ].concat(...inArray);

  B. [ ].concat.apply(inArray,[ ]);

  C. [ ].concat([...inArray])

  D. [ ].concat.apply([ ],inArray);

  Correct Answer: AD

• Question 204:

  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

  Correct Answer: D

• Question 205:

  Given the HTML below:

  

  Which statement adds the priority-account CSS class to the Universal Containers row?

  A. document. querySelector (#row-uc').classes-push('priority-account');

  B. document. getElementByid('row-uc').addClass('priority-account*);

  C. document. querySelectorAll('#row-uc') -classList.add("priority-accour');

  D. document. queryselector('#row-uc').ClassList.add('priority-account');

  Correct Answer: D

• Question 206:

  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 2

  completed"));

  04 let car3 = new Promise(resolve => setTimeout (resolve, 3000, "Car 3

  Completed"));

  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.

  Correct Answer: C

• Question 207:

  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 = Array.from(arr1);

  C. Let arr2 = arr1;

  D. Let arr2 = arr1.sort();

  Correct Answer: AB

• Question 208:

  A developer wants to use atry...catch statement to catch any error that countSheep () may throw and pass it to a handleError () function. What is the correct implementation of the try...catch?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: A

• Question 209:

  Refer to the code below:

  

  Whatis the value of result after line 10 executes?

  A. Error: myFather.job is not a function

  B. John Developer

  C. undefined Developer

  D. John undefined

  Correct Answer: B

• Question 210:

  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 the package, jsondefinition below.

  

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

  A. 1.3.1

  B. 1.3.5

  C. The command fails, because version 130 is not found

  D. 1.4.0

  Correct Answer: B