Building a Custom Image Upload and Preview Component in React with TypeScript
To implement a custom image upload and preview feature in a React component using TypeScript, you can follow these steps: Step 1: Set Up the Component First, create a state to handle the selected file and its preview URL. Step 2: Styling the Component You can add styles for the custom upload button and preview […]
JavaScript interview questions 2024 (with Answers)
Here are the answers to the JavaScript interview questions: 1. Basic Concepts 2. Functions and Scope 3. Objects and Prototypes 4. Asynchronous JavaScript 5. Error Handling 6. JavaScript in the Browser : Stores data with no expiration time. The data persists even after the browser is closed and reopened.– sessionStorage: Stores data for the duration […]
Master Dynamic Copyright Updates with JavaScript
Bid farewell to manually updating copyright dates and embrace the elegance of JavaScript for future-proof copyright displays. This timeless technique ensures your website effortlessly reflects the present year, maintaining a polished and professional image while saving you precious time. The copyright text is an essential and must-have element in the footer section of the webpage. […]
101 JavaScript Interview Questions with Answers for Successful Interviews
Here are 101 JavaScript interview questions with answers: 1. What is JavaScript? JavaScript is a high-level, interpreted programming language used primarily for creating interactive web pages. 2. What are the different data types in JavaScript? The data types in JavaScript include string, number, boolean, object, undefined, and null. 3. What is the difference between null and undefined? null represents the […]
Why are Actions Not Allowed in Strict Mode?
Some typical actions that are forbidden in strict mode are given below: 1. Undeclared objects or variables. We have already seen that using a variable or an object without declaring it is not allowed in strict mode. Example: Output: user = {referenceError: User is not defined 2. Deleting an object, variable, or function. Example: Output: […]
Activating JavaScript Strict Mode in Individual Functions
You can also enable string mode for a particular function by adding ‘use strict’; or “use strict”; at the beginning of the function. Syntax: functionfunctionName() { ‘use strict’; // function body}// orfunctionfunctionName() { “use strict”; // function body} This statement should be the first statement of the function excluding comments. Adding ‘use strict’; or “use strict”; at the beginning […]
JavaScript Strict Mode: What it Does and Doesn’t AllowJavaScript Strict Mode: What it Does and Doesn’t Allow
In this tutorial, you will learn about the strict mode in JavaSript, the process of activating strict mode for a program or an individual function in JavaScript, and some typical actions that are forbidden by strict mode in JavaScript. Activating JavaScript Strict mode For activating Strict mode, you can add ‘use strict’; or “use strict”; at the […]
Q. Explain what a callback function is and provide a simple example
A callback the function is a function that is passed to another function as an argument and is executed after some operation has been completed. Below is an example of a simple callback function that logs to the console after some operations have been completed.
Q. Explain arrays in JavaScript
An array is an object that holds values (of any type) not particularly in named properties/keys, but rather in numerically indexed positions:
Q. Explain is Scope in JavaScript?
In JavaScript, each function gets its own scope. The scope is basically a collection of variables as well as the rules for how those variables are accessed by name. Only code inside that function can access that function’s scoped variables. A variable name has to be unique within the same scope. A scope can be nested […]
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