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Every time JavaScript code runs, it does so within an Execution Context. You can think of this as an environment or a wrapper that manages the execution of the current code. There are two main types of execution contexts:
When to use which array method for data manipulation?
Memoization optimization caches the results of expensive function calls and returns the cached result when the same inputs occur again. javascript
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Explain how to convert a function with multiple arguments into a sequence of functions. How to Get the Most Out of the PDF
Understanding global, function, and block scope.
Use case: Infinite scroll features where you need to check how close the user is to the bottom of the page every 200ms. javascript
6. What is Polyfilling? Write a Polyfill for Array.prototype.map . Excited by the prospect of acing his interviews,
function removeDuplicates(arr) return [...new Set(arr)]; console.log(removeDuplicates([1, 2, 2, 3, 4, 4, 5])); // Output: [1, 2, 3, 4, 5] Use code with caution. Checking for Anagrams
Variables declared with var are hoisted and automatically initialized with a value of undefined . You can access a var variable before its formal declaration line without throwing an error.
: Syntactic sugar built over promises. It makes asynchronous code read like synchronous code, improving readability and simplifying error handling with standard try/catch blocks. 4. Common Coding Challenges Challenge 1: Implement a Custom Array.prototype.map
Invokes the function immediately. It accepts the this context as the first argument, followed by individual arguments passed sequentially, separated by commas. You can think of this as an environment
Hoisted and initialized as undefined . You can access a var variable before its declaration line without a crash.
: Duplicates every structural layer recursively, breaking all reference links to the original object. Created using structuredClone(obj) or JSON.parse(JSON.stringify(obj)) . What is Currying?
Objects inherit directly from other objects via a prototype chain. Every JavaScript object has a hidden private property ( [[Prototype]] ) linking to another object. Even modern JavaScript class syntax is just syntactic sugar over prototypal inheritance. Q4: How do call() , apply() , and bind() differ?
