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Tricky Question

jihadchowdhory profile image jihadChowdhory ・2 min read

1/ Null vs Undefined
In JavaScript, undefined is a type, whereas null an object. It means a variable declared, but no value has been assigned a value. Whereas, null in JavaScript is an assignment value.

2/ Double equal vs Triple equal
Double Equals (==) checks for value equality only. It inherently does type coercion. This means that before checking the values, it converts the types of the variables to match each other. On the other hand, Triple Equals (===) does not perform type coercion. It will verify whether the variables being compared have both the same value and the same type.

3/ Scope
Scope is the accessibility of variables, functions, and objects in some particular part of your code during runtime. In other words, scope determines the visibility of variables and other resources in areas of your code.

4/ Window
JavaScript Window is a global Interface (object type) that is used to control the browser window lifecycle and perform various operations on it.

5/ This keyword
this keyword refers to an object, that object which is executing the current bit of javascript code. In other words, every javascript function while executing has a reference to its current execution context, called this. Execution context means here is how the function is called.

6/ Event Bubble
Event bubbling is a term you might have come across on your JavaScript travels. It relates to the order in which event handlers are called when one element is nested inside a second element, and both elements have registered a listener for the same event.

7/ Event Delegate
JavaScript event delegation is a simple technique by which you add a single event handler to a parent element in order to avoid having to add event handlers to multiple child elements.

8/ Javascript
JavaScript is a text-based programming language used both on the client-side and server-side that allows you to make web pages interactive. Where HTML and CSS are languages that give structure and style to web pages, JavaScript gives web pages interactive elements that engage a user.

9/ Recursion vs Iteration
The concept of Recursion and Iteration is to execute a set of instructions repeatedly. The difference between them is that recursion is simply a method call in which the method being called is the same as the one making the call while iteration is when a loop is repeatedly executed until a certain condition is met.

10/ Arrow Function
Arrow function is one of the features introduced in the ES6 version of JavaScript. It allows you to create functions in a cleaner way compared to regular functions.

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