Salesforce Certified JavaScript Developer I Practice Test - Questions Answers, Page 7

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

is below:

<input type="file" onchange="previewFile()">

<img src="" height="200" alt="Image Preview…"/>

The JavaScript portion is:

01 function previewFile(){

02 const preview = document.querySelector('img');

03 const file = document.querySelector('input[type=file]').files[0];

04 //line 4 code

05 reader.addEventListener("load", () => {

06 preview.src = reader.result;

07 },false);

08 //line 8 code

09 }

In lines 04 and 08, which code allows the user to select an image from their local computer , and to display the image in the browser?

A developer creates a generic function to log custom messages in the console. To do this, the function below is implemented.

01 function logStatus(status){

02 console./*Answer goes here*/{'Item status is: %s', status};

03 }

Which three console logging methods allow the use of string substitution in line 02?

A developer wrote the following code:

01 let X = object.value;

02

03 try {

04 handleObjectValue(X);

05 } catch (error) {

06 handleError(error);

07 }

The developer has a getNextValue function to execute after handleObjectValue(), but does not want to execute getNextValue() if an error occurs.

How can the developer change the code to ensure this behavior?

Refer to the code:

Given the code above, which three properties are set pet1?

Choose 3 answers:

Refer to the code below:

Let car1 = new Promise((_ , reject) =>

setTimeout(reject, 2000, "car 1 crashed in" =>

Let car2 =new Promise(resolve => setTimeout(resolve, 1500, "car 2 completed")

Let car3 =new Promise(resolve => setTimeout(resolve, 3000, "car 3 completed")

Promise.race(( car1, car2, car3))

.then (value => (

Let result = '$(value) the race.';)}

.catch(arr => {

console.log("Race is cancelled.", err);

});

What is the value of result when Promise.race executes?

Refer to the following code:

Let sampleText = 'The quick brown fox jumps';

A developer needs to determine if a certain substring is part of a string.

Which three expressions return true for the given substring ?

Choose 3 answers

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:

Cloud Kicks has a class to represent items for sale in an online store, as shown below:

Class Item{ constructor (name, price){ this.name = name; this.price = price;

} formattedPrice(){ return 's' + String(this.price);}} A new business requirement comes in that requests a ClothingItem class that should have all of the properties and methods of the Item class but will also have properties that are specific to clothes.

Which line of code properly declares the clothingItem class such that it inherits from Item?