On null and undefined in JavaScript

The concept of an object, record, structure, or product type occurs in almost every programming language. Being able to declare a type of value that groups a number of other values together is a fundamentally useful thing. As similar as the various record-ish constructs are in their basic functionality, the way such values are actually looked at...

CodeMirror 6 is a new code editor library for the web, a from-scratch implementation based on the experience of building and maintaining versions 1 to 5 for the past 13 years. It aims to be more extensible and accessible than previous versions. As of today, version 6.0 is stable. Going forward, probably at least several years, all new releases...

An extensible system, at its base, is a system that allows people to add additional functionality that was not anticipated by the core system. A good extensible system also makes sure multiple extensions that don't know anything about each other can be combined, and compose in ways that don't cause problems. The problem has several aspects....

I'm happy to announce that with version 0.8.0 the CodeMirror 6 project is entering its beta phase, and you're very much invited to start trying it out and poking at it. Roughly, this “beta” status means: I actually like the current programming interface. Apart from the move from a mono-package to a group of separate packages (removing the next/...

This post describes the considerations that came up in designing the document-change data structure and built-in collaborative editing feature in the upcoming version of CodeMirror (a code editor system). It is something of a followup to the Collaborative Editing in ProseMirror post. I won't introduce anything new or exciting here—the design I...