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JavaScript Tricky Interview Questions
- Aniaya Murthy
- 28th Dec, 2022
- 934 Followers
JavaScript Tricky Interview Questions
Practice here the best JavaScript Tricky Interview Questions and Answers.
JavaScript Tricky Interview Questions
1) What is Coercion in JavaScript?
Type coercion is the process of converting value from one type to another (such as string to number, object to boolean, and so on)
2) How would you check if a number is an integer?
By using Number.isInteger() function
3) What is Object Equality in Javascript?
In JavaScript, Object Equality is used for two purposes basically. "==" is used for comparing two variables by ignoring its data type whereas "===" is used for comparing two variables by checking its data type.
4) Why to use === instead of ==?
"===" is used instead of "==" because it can compare two variables by checking data type.
5) What is difference between typeof and instanceof?
typeof() is a unary operator that returns a string indicating the type of the unevaluated operand whereas instanceof() is a binary operator, accepting an object and a constructor that returns a boolean indicating whether or not the object has the given constructor in its prototype chain.
6) Which one you use to delete an element from javascript array slice or delete?
To delete an element from the javascript array you can use the following technique:
- pop - Removes from the End of an Array.
- shift - Removes from the beginning of an Array.
- splice - removes from a specific Array index.
- filter - allows you to programmatically remove elements from an Array.
7) How to create an object whose prototype is a given object?
You can create an object whose prototype is a given object by the given method i.e. var o = Object. create(Object); it creates a new blank object o whose prototype is the Object function.
8) How to add a number to two varible in once?
To add a number to two variables at once with the help of the following example( foo += -bar + (bar += x)) where x is the number that is added to both variablLinting is the process of running a program that analyses your code for programmatic and stylistic errors.
9) How to get URL and and its parts in JavaScript?
The steps to get URL and and its parts in JavaScript are:
- window.location.protocol = “http:”
- window.location.host = “css-tricks.com”
- window.location.pathname = “/example/index.html”
- window.location.search = “? s=flexbox”
10) Write code to strip whitespaces from String in JavaScript?
str.trim() method is used to remove the white spaces from both the ends of the given string.
Syntax:
str.trim()
Return value: This method returns a new string, without any of the leading or the trailing white spaces.
You can use the following code to strip whitespaces from String in JavaScript:
<!DOCTYPE html>
<html>
<head>
<title>
How to remove spaces from
a string using JavaScript?
</title>
</head>
<body>
<h1 style="color: green">
Online Interview Questions
</h1>
<b>
How to remove spaces from
a string using JavaScript?
</b>
<p>
Original string is:
Online Interviews Questions
</p>
<p>
New String is:
<span class="output"></span>
</p>
<button onclick="removeSpaces()">
Remove Spaces
</button>
<script type="text/javascript">
function removeSpaces() {
originalText =
"Online Interviews Questions";
newText =
originalText.replace(/ /g, "");
document.querySelector('.output').textContent
= newText;
}
</script>
</body>
</html>
Output:
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