JavaScript Array reduce Explained Real Examples + Polyfill Implementation
In this video, we deep dive into the JavaScript Array reduce() method — one of the most powerful and advanced array methods.
🔹 What is reduce()?
🔹 How reduce() works internally
🔹 Why and when we use reduce()
🔹 Real world use cases (sum, flatten array, count occurrences, etc.)
🔹 Polyfill of reduce() — build your own reduce function!
reduce() takes an array and reduces it to a single value (number, object, array... anything!).
This method is unavoidable in functional programming and is very commonly asked in JavaScript interviews.
✅ After watching this video, you will:
Understand how reduce() works step-by-step
Know when to use reduce()
Write your own polyfill for reduce()
Use reduce() in real-world scenarios
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