Day 67 / 100 Days of Code: Iterating with Methods

#100daysofcode #webdev #javascript #beginners

Thu, September 5, 2024

Hello everyone! 👋

Iterators are yet another JavaScript power tool. In a slight twist, while today’s assignment is named Iterators: .forEach(), .map(), .findIndex(), .filter(), and .reduce(), to be transparent, these are methods that employ iterators to accomplish their purpose.

Iterator Methods Overview
.forEach(): Iterates elements & performs the provided function
.map(): Iterates elements & applies function to create a new array
.findIndex(): Iterates elements, finds match & returns the index
.reduce(): Iterates elements & accumulates values, summation
.filter(): Iterates elements & conditionally creates new array
These methods belong to the Array prototype object and abstract the mundane iterative process to directly expose the data.

Favorite Iterator of the Day: .filter()
After exploring and experimenting with these iterators today, I found that my favorite is .filter() because of its extensibility. A little bit like a factory function, it can be used to create new objects, as long as they’re subsets of the object matching a condition, such as all elements over a certain amount:


const bigNumbers = [148, 256, 384, 918, 512];

// Using filter() to get all elements above 200
const allAbove200 = bigNumbers.filter(num => num > 200);

console.log(allAbove200); // Output: [256, 384, 918, 512]