Debate in JavaScript Community Over Proposed Types Syntax – InApps 2022

If a proposal unveiled this week gets its way, JavaScript developers will soon have something that many of them have long been asking for: a type system, of some sort at least.

A blog post by TypeScript senior program manager Daniel Rosenwasser lays out the background and reasoning for the proposal for type syntax in JavaScript. He writes that “if we pull this all off, we have the chance to make one of the most impactful improvements to the world of JavaScript.”

Feel free to read the proposal (it’s quite readable), but for those of us wanting the TL;DR, here it is: if the proposal gets accepted into the language, this will be valid JavaScript: pic.twitter.com/hHkjFLQP34

— Gil Tayar (@giltayar) March 10, 2022

The proposal, which shares authors from Microsoft, Bloomberg, Igalia, and a number of other sources, suggests that JavaScript developers should be able to “add type annotations to their JavaScript code, allowing those annotations to be checked by a type checker that is external to JavaScript” and then be ignored at runtime.

“Because this new syntax wouldn’t change how surrounding code runs, it would effectively act as comments,” writes Rosenwasser in his blog post, later adding that “JavaScript could carve out a set of syntax for types that engines would entirely ignore, but which tools like TypeScript, Flow, and others could use. This allows us to keep the things you love about TypeScript — its type-checking and editing experience – while removing the need for a build step in development.”

this is absolutely huge — the biggest thing to happen to javascript in a long time. may this proposal sail quickly through calm waters https://t.co/67qOJ8qtbc

— Rich Harris (@Rich_Harris) March 9, 2022

Up until now, types were relegated to TypeScript partly because this build step could also be used to compile code for the various browsers. With the advent of continuously updated evergreen browsers, however, the proposal’s authors write that they “anticipate there will be less need for developers to downlevel-compile” and therefore, “for many TypeScript users, the only necessary step between writing code and running it will be to erase away type annotations.”

One noteworthy part of the proposal lays out exactly what is not being proposed:

“Our team isn’t proposing putting TypeScript’s type-checking in every browser and JavaScript runtime – nor are we proposing any new type-checker to be put in the browser. We think doing that would cause problems for JavaScript and TypeScript users alike due to a range of issues, such as runtime performance, compatibility issues with existing TypeScript code, and the risk of halting innovation in the type-checking space.”

Similarly, several features from TypeScript that generate code, such as enums, namespaces, and parameter properties, are being explicitly excluded “because they have runtime semantics, generating JavaScript code rather than simply being stripped out and ignored.”

As you might expect, the potential addition of types to JavaScript — even completely optional ones — is not something that absolutely everyone agrees on.

This is a Very Bad Thing for JavaScript.

Here’s why https://t.co/TytQZYWhO7

— Jess Telford (@JessTelford) March 10, 2022

For many detractors, the argument is that the addition of types as comments will unnecessarily complicate code visually and make it harder for new developers. They also argue that, lest code suffer from bloat, an extra step will still be necessary anyway in order to remove that code. Others still argue that there is a reason that TypeScript is TypeScript, and not JavaScript, but they perhaps miss that this proposal intentionally excludes a number of TypeScript features.

“This proposal is a balancing act: trying to be as TypeScript compatible as possible while still allowing other type systems, and also not impeding the evolution of JavaScript’s syntax too much,” the proposal offers on the point.

I have had a chance to chew on this a bit and my take is more nuanced now.

As with a lot of decisions in tech, this proposal is a matter of tradeoffs and the weight different people will attribute to various factors will fluctuate

My thoughts:

(buckle up, it’s a long one) https://t.co/YqqszuHr0t

— Alex Reardon (@alexandereardon) March 10, 2022

As the proposal’s authors note, the proposal itself is presented as a “strawperson proposal” and, as such, intended to spark precisely this sort of lively debate. Thus far, it would appear that there is debate aplenty, alongside a rather robust enthusiasm for the advent of type functionality coming to a JavaScript near you.

This Week in Programming

• Google’s Summer of Code Drops Mentor List: For those of you considering applying to Google Summer of Code (GSoC) 2022, the list of mentoring organizations has been revealed. It adds 32 new organizations, to bring the total to 203 open source projects. The organizations include a variety of foundations — the Linux Foundation, the Cloud Native Computing Foundation, the Eclipse Foundation, the Python Software Foundation, to name just some — and open source projects like TensorFlow, GitLab, Jenkins, Dart, Ruby, Julia, and many more. The GSoC runs every (northern hemisphere) summer, mentoring developers in the ways of open source software contribution. Applications open on Monday, April 4 and end on Tuesday, April 19.
• The DHH Drama Fallout Continues: Last week, we related how Ruby on Rails creator DHH and RailsConf went their separate ways after the RailsConf team asked him to share the keynote stage, and this week the fallout continued, as Rails core team member Kasper Timm Hansen rather abruptly left the core team. Hansen had signaled his displeasure over the situation a week earlier, when he tweeted that he’d rather not be mentioned in DHH’s blog posts, and shortly thereafter issued the pull request that simply stated “I’m leaving Rails core and I’m not interested in being in the alumni.” There was a good amount of fanfare when Kasper joined the Rails core and, if the responses to his tweet and pull requests are any indication, the eleventh most productive contributor to Rails looks like he will be missed by the community at large.
• Embedded Software Development Comes to VS Code: Following a similar launch for Visual Studio 2022, Microsoft has released the Embedded Tools extension for Visual Studio Code, which, according to the extension’s description “provides a register viewer for CMSIS-SVD files, and an RTOS data viewer with support for Azure RTOS and FreeRTOS.” The extension, used alongside the new vcpkg artifact capabilities that helps acquire embedded tool dependencies, allows developers to quickly bootstrap an embedded development machine and get started. With the addition of this extension, VS Code now offers developers all of the usual features, including code navigation, IntelliSense, build, deploy, debugging, and new diagnostic capabilities around peripheral registers and real-time operating system (RTOS) object views.

With JavaScript you can save a few minutes by not declaring types!

(Warning: ⚠️ You’ll probably waste all those “saved” minutes debugging runtime errors) https://t.co/qFi5H9aOe1

— Cory House (@housecor) January 8, 2022