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Some drops of JavaScript

Welcome to Some drops of JavaScript

The reason why

This book collects some useful, unknown, underrated JavaScript functions or stuff discovered, used, and learned during JavaScript daily use.

Using JavaScript frameworks/libraries daily (like React, Vue, Angular, Svelte), sometimes the perception of the power of the language and the basic functionalities provided by the JavaScript core could be lost. I see that usually, I used to look at the framework documentation or look for a package in Npm for the system, array, and string functions instead of using core functionalities provided by the language.

While I wrote this HTML-book, I also wrote some scripts to better understand the behavior of the functions. You can find these examples here: in the examples directory.


The code used in this book is tested with Bun and NodeJs version 18 (LTS).

Bun is a JavaScript runtime, package manager, bundler and test runner built from scratch using the Zig programming language. It was designed by Jarred Sumner as a drop-in replacement for Node.js. Bun uses JavaScriptCore as the JavaScript engine, unlike Node.js and Deno, which both use V8. The official website is: .

Node.js is an open-source, cross-platform JavaScript runtime environment, and you can obtain Node.js on the official website.

Continuous release

I was thinking to print this book, but I think that is not so eco-friendly and a book about development could be improved daily in terms of spellchecking and the content and examples. So, I expect to adopt the same approach in the software with the CI/CD, with a continuous release of the book.


  • W.I.P. the 1.0.0 version is not yet released: writing… ;

The book is Work in Progress, the list of the functions covered by the book at the moment are listed in file

So, if you have any feedback, or you want to suggest some corrections, feel free to open an issue here:

Where to find this book

This book is available for download for free here:

Thanks to…

Thanks to all the Open Source community.


”Some drops of JavaScript” (c) by Roberto Butti

”Some drops of JavaScript” is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

You should have received a copy of the license along with this work. If not, see