Q21. What is the difference between == and === operators?
JavaScript provides two types of equality operators: - **Loose equality (`==`, `!=`)**: Performs type conversion if the types differ, comparing values after converting th...
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Q22. What causes hydration mismatches and how do you fix them?
Hydration is React attaching event handlers to server-rendered HTML. A mismatch happens when the server HTML differs from the client's first render, and React warns and r...
Q23. How does zone.js drive change detection and what changes with zoneless Angular?
Historically Angular relied on zone.js, which monkey-patches async APIs such as setTimeout, promises, XHR and event listeners so the framework knows when something might ...
Q24. What are lambda expressions or arrow functions?
**Arrow functions** (also known as "lambda expressions") provide a concise syntax for writing function expressions in JavaScript. Introduced in ES6, arrow functions are o...
Q25. What is Next.js?
**Next.js** is an open-source React framework developed and maintained by Vercel that enables developers to build high-performance, full-stack web applications. ### Core ...
Q26. What is a first class function?
In JavaScript, **first-class functions(first-class citizens)** mean that functions are treated like any other variable. That means: 1. You can assign a function to a vari...
Q27. How do you create a new Next.js project?
The officially supported and recommended way to scaffold a new Next.js application is using **`create-next-app`**: ```bash npx create-next-app@latest ``` ### Interactive ...
Q28. What is a first order function?
A first-order function is a function that doesn’t accept another function as an argument and doesn’t return a function as its return value. i.e, It's a regular function t...
Q29. What is the purpose of the `pages or app` directory in Next.js?
The `pages` and `app` directories in Next.js represent the **routing and layout backbone** of the application. Next.js uses file-system based routing, meaning your filesy...
Q30. What is a higher order function?
A higher-order function is a function that either accepts another function as an argument, returns a function as its result, or both. This concept is a core part of JavaS...