JavaScript Array Methods: Map, Filter & Reduce Explained - Array Manipulation
Are you still writing long for loops to manipulate arrays? In this video, we master the three most powerful Higher Order Functions in JavaScript: Map, Filter, and Reduce.
These methods allow you to write cleaner, shorter, and more readable code. We break down exactly
when to use each one with practical examples.
Topics Covered in this Video:
00:00 - Introduction
00:22 - Array.map(): Transforming data (e.g., Modifying every element)
01:05 - Array.filter(): Selecting specific data (e.g., Finding numbers greater than 10)
01:30 - Array.reduce(): Accumulating a result (e.g., Summing a list of numbers)
02:38 - Demo: Using .map() to modify strings/numbers
06:38 - Demo: Using .filter() to extract specific values
08:53 - Demo: Using .reduce() to calculate a total sum
Concept Cheatsheet:
Map: Returns a new array of the same length (Transforms data).
Filter: Returns a new array with fewer items (Selects data).
Reduce: Returns a single value (Accumulates data).
Why is this important for QA?
If you use Cypress, Playwright, or WebDriverIO, you constantly handle lists of web elements.
Use .map() to get a list of text from a list of elements.
Use .filter() to find a specific product in a table.
Use .reduce() to verify the total price in a shopping cart.
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