Salesforce JAVASCRIPT-DEVELOPER-I Online Practice Questions and Exam Preparation

Salesforce JAVASCRIPT-DEVELOPER-I Online Questions & Answers

• Question 151:

  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)
  A. value == NaN
  E. Number.isNaN(value)

• Question 152:

  Which statement parses successfully?

  A. JSON. parse (""foo"');
  B. JSON.parse (""foo'");
  C. JSON.parse ("foo");
  D. JSON.parse ("foo");
  A. JSON. parse (""foo"');

• Question 153:

  What is the result of the code block?

  A. The console logs only `flag'.
  B. The console logs `flag' and another flag.
  C. An error is thrown.
  D. The console logs `flag' and then an error is thrown.
  D. The console logs `flag' and then an error is thrown.

• Question 154:

  Referto the code below: Const pi = 3.1415326, What is the data type of pi?

  A. Double
  B. Number
  C. Decimal
  D. Float
  B. Number

• Question 155:

  developer has a web server running with Node.js. The command to start the web server is node server,js. The web server started having latency issues. Instead of a one second turn 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 the latency 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
  C. DEBUG =true node server.js

• Question 156:

  Given the code below:

  const delay = async delay =>{

  return new Promise((resolve,reject)=>{

  console.log(1);

  setTimeout(resolve,deleay);

  });

  };

  const callDelay =async ()=>{

  console.log(2);

  const yup = await delay(1000);

  console.log(3);

  }

  console.log(4);

  callDelay();

  console.log(5);

  What is logged to the console?

  A. 4 2 1 5 3
  B. PlaceHolder
  C. PlaceHolder
  D. PlaceHolder
  A. 4 2 1 5 3

• Question 157:

  Refer to code below:

  Function muFunction(reassign){

  Let x = 1;

  var y = 1;

  if( reassign ) {

  Let x= 2;

  Var y = 2;

  console.log(x);

  console.log(y);}

  console.log(x);

  console.log(y);}

  What is displayed when my Function(true) is called?

  A. 2 21 1
  B. 2 2 undefined undefined
  C. 2 2 1 2
  D. 2 2 2 2
  C. 2 2 1 2

• Question 158:

  At Universal Containers, every team has its own way of copyingJavaScript objects. The code

  Snippet shows an implementation from one team:

  Function Person() {

  this.firstName = "John";

  this.lastName = `Doe';

  This.name =() => (

  console.log(`Hello $(this.firstName) $(this.firstName)');

  )}

  Const john = new Person ();

  Const dan = JSON.parse(JSON.stringify(john));

  dan.firstName ='Dan';

  dan.name();

  What is the Output of the code execution?

  A. Hello Dan Doe
  B. Hello John DOe
  C. TypeError: dan.name is not a function
  D. TypeError: Assignment to constant variable.
  C. TypeError: dan.name is not a function

• Question 159:

  What are two unique features of functions defined with a fat arrow as compared to normal function definition? Choose 2 answers

  A. The function generated its own this making it useful for separating the function's scope from itsenclosing scope.
  B. The function receives an argument that is always in scope, called parentThis, which is the enclosing lexical scope.
  C. If the function has a single expression in the function body, the expression will be evaluated and implicit returned.
  D. The function uses the this from the enclosing scope.
  A. The function generated its own this making it useful for separating the function's scope from itsenclosing scope.
  B. The function receives an argument that is always in scope, called parentThis, which is the enclosing lexical scope.

• Question 160:

  A developer has an Error Handler module that contains multiple functions. What kind of export be leverages so that multiple functions can be used?

  A. Named
  B. All
  C. Multi
  D. Default
  A. Named