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Salesforce Certified JavaScript Developer I Practice Test - Questions Answers, Page 10

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Question 91

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Given the code below: const copy = JSON.stringify([ new String(' false '), new Bollean( false ), undefined ]); What is the value of copy?

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Question 92

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The developer wants to test the array shown: const arr = Array(5).fill(0) Which two tests are the most accurate for this array ?

Choose 2 answers:

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Question 93

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A developer receives a comment from the Tech Lead that the code given below has error:

error:

const monthName = 'July';

const year = 2019;

if(year === 2019) {

monthName = 'June';

Which line edit should be made to make this code run?

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Question 94

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Refer to the following code:

<html lang="en">

<body>

<div onclick = "console.log('Outer message') ;">

<button id ="myButton">CLick me<button>

</div>

</body>

<script>

function displayMessage(ev) {

ev.stopPropagation();

console.log('Inner message.');

}

const elem = document.getElementById('myButton');

elem.addEventListener('click' , displayMessage);

</script>

</html> What will the console show when the button is clicked?

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Question 95

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Refer to the code below: function foo () { const a =2; function bat() { console.log(a);

} return bar;

} Why does the function bar have access to variable a ?

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Question 96

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Given the following code:

document.body.addEventListener(' click ', (event) => {

if (/* CODE REPLACEMENT HERE */) {

console.log('button clicked!');

)

});

Which replacement for the conditional statement on line 02 allows a developer to correctly determine that a button on page is clicked?

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Question 97

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Given the following code:

document.body.addEventListener(' click ', (event) => {

if (/* CODE REPLACEMENT HERE */) {

console.log('button clicked!');

)

});

Which replacement for the conditional statement on line 02 allows a developer to correctly determine that a button on page is clicked?

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Question 98

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Universal Container(UC) just launched a new landing page, but users complain that the website is slow. A developer found some functions that cause this problem. To verify this, the developer decides to do everything and log the time each of these three suspicious functions consumes.

console.time('Performance');

maybeAHeavyFunction();

thisCouldTakeTooLong();

orMaybeThisOne();

console.endTime('Performance');

Which function can the developer use to obtain the time spent by every one of the three functions?

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Question 99

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Refer to the code below:

console.log(''start);

Promise.resolve('Success') .then(function(value){

console.log('Success');

});

console.log('End');

What is the output after the code executes successfully?

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Question 100

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Refer to HTML below:

<div id ="main">

<div id = " card-00">This card is smaller.</div>

<div id = "card-01">The width and height of this card is determined by its contents.</div>

</div> Which expression outputs the screen width of the element with the ID card-01?

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Refer to the following code: &lt;html lang="en"&gt; &lt;body&gt; &lt;div onclick = "console.log('Outer message') ;"&gt; &lt;button id ="myButton"&gt;CLick me&lt;button&gt; &lt;/div&gt; &lt;/body&gt; &lt;script&gt; function displayMessage(ev) { ev.stopPropagation(); console.log('Inner message.'); } const elem = document.getElementById('myButton'); elem.addEventListener('click' , displayMessage); &lt;/script&gt; &lt;/html&gt; What will the console show when the button is clicked?
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