Q51. What is optional chaining?
According to MDN official docs, the optional chaining operator (?.) permits reading the value of a property located deep within a chain of connected objects without havin...
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Q52. What are the phases of execution context?
The execution context in JavaScript is a data structure that stores the information necessary for executing a piece of code. It includes the code itself, the values of th...
Q53. What are the optimization techniques of V8 engine?
V8 engine uses the below optimization techniques. 1. **Inline expansion:** It is a compiler optimization by replacing the function calls with the corresponding function b...
Q54. What are hidden classes?
Since JavaScript is a dynamic programming language, you can add or remove properties and methods from objects on the fly at runtime. This nature of JavaScript increases t...
Q55. What is inline caching?
Inline caching is an optimization technique based on the observation that repeated calls to same function tends to occur on same type of objects. The V8 compiler stores a...
Q56. What is structuredClone and how is it used for deep copying objects?
In JavaScript, `structuredClone()` is a built-in method used to create a **deep copy** of a value. It safely clones nested objects, arrays, Maps, Sets, Dates, TypedArrays...
Q57. What is the difference between const and Object.freeze?
The main difference is that `const` applies to **variables** (bindings), while `Object.freeze()` applies to **values** (objects). 1. **`const`**: Prevents the reassignmen...
Q58. What are Proxy traps and what operations can they intercept?
Proxy traps are handler methods that intercept fundamental operations on objects, allowing you to customize their behavior. **Available traps:** ```javascript const handl...
Q59. How do you prevent prototype pollution attacks in JavaScript?
Prototype pollution is a security vulnerability where attackers inject properties into Object.prototype, affecting all objects in the application. **Vulnerable code:** ``...
Q60. What is the Document Object Model (DOM)?
The DOM (Document Object Model) is a programming interface that represents the structure and content of an HTML document as a tree-like structure of nodes. It allows deve...