Frontend

• An in-depth guide on building your own 100% reactive renderer from scratch.
• A must-read research on CPU cost of JavaScript.
• Bootstrap 5 alpha is out! This time no jQuery and no IE11.
• A guided tour of what it is like to work on the SpiderMonkey (JavaScript engine) compiler and improve conformance with ECMA-262, the JavaScript Specification. From Mozilla to people with love.

Node.js

• Sad to say it, but it looks like hapi.js project is reaching its end. If you happen to use hapi.js, you should consider switching to another web framework in the nearest future.
• As of v7 npm support both yarn.lock and package-lock.json. Here is a great read on npm v7 treats them and about the future of npm dependency resolution algorithms.

Java

• HotSpot JVM has tons of optimizations all over the place. For instance, even the default hashCode() hides some secrets. Learn more about this optimization here.
• As an interesting follow-up, you might want to take a look at the j.l.String#hashCode() implementation which caches the hash code in a non-volatile hash field. This optimization was described in the Java Concurrency in Practice book here and here. Do not do it at home!
• If you are not familiar with the history behind Generics, which have a controversial reputation in Java community, you should read this post from Brian Goetz.

General

• Jepsen team recently did an analysis of RedisRaft, a new module that provides strict serializability for Redis. As usual, some issues were found. As usual, some promises of fixes were made.