Most efficient way to convert an HTMLCollection to an Array

HTMLCollection vs. Array: Why and When to Convert

While HTMLCollections are fancy, automatically updating whenever the document changes, they lack many of the cool tricks (methods) provided by Arrays. Hence, to take advantage of the full power of Array methods like map(), filter(), and reduce(), converting the HTMLCollection is key.

Modern ES6 Converters vs. Time-Tried Techniques

The ECMAScript 2015 (ES6) syntax introduced more readable and concise ways to morph collections like HTMLCollection into arrays. We have the spread operator (...), Array.from() method, as well as good old Array.prototype.slice.call.

• Spread operator: Converts array-like objects like HTMLCollection and also iterables like NodeList into arrays.
• Array.from(): Straightforward conversion with an option to include a mapping function for element transformation.

Conversion Techniques Exemplified

Going Modern with Array.from()

The Array.from() method is handy for an easy conversion. The cherry on the cake — you can specify a mapping function during conversion.

const pageLinksAsText = Array.from(document.links, link => link.textContent);
// -> capturing link content as text, like a web-crawling spider
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Classic Charm: slice.call()

Somewhat less modern but revered for its broad browser support, is the Array.prototype.slice.call.

const arrayOfImages = [].slice.call(document.images);
// -> snatching images off the page like an art thief
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Performance Edge

Choosing a method based on speed alone is usually not the smartest move. The differences are mostly inconsequential for small-to-moderate-sized collections. Readability and extra functionalities, like Array.from()'s mapping feature, often outbalance any millisecond advantages.

Good Practices for Conversion

Embrace Clarity with the Spread Operator

The spread operator is loved for its readability and conciseness. It's transparent about what it does: Battling the universe and capturing it in an Array.

const marvelComicsInArray = [...document.getElementsByClassName('marvel-comics')];
// -> signing your own comic heist
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Future-Proof Your Code

Adopting ES6 syntax like Array.from() or spread operator is a good choice for future-proofing your code. However, bear in mind the need for polyfills in older environments.

Avoid Lengthy For Loops

Stay away from manual loops like for or while for conversion. They not only spawn more opportunities for errors but also slower and significantly more verbose than these methods.

Use Case Dictates the Way

No single method is a one-size-fits-all solution. Always consider your specific use case. E.g., use Array.from() with a mapping function when you need to transform collection items.

Which Conversion Method to Use? A Guide

For Express Conversions

Use the spread operator for a lightning-fast, yet clean conversion when no extra manipulation is needed.

For Transformations on the Fly

Need to map or modify the elements during conversion? Array.from() is your partner in crime.

When Compatibility is Priority

Working on older codebases or need to support older browsers? Array.prototype.slice.call's broad compatibility might swing the balance in its favor.