Questions about systemjs

[guybedford]

I'm glad you like it. It is very early days, and my documentation is very much lacking, so I hope I'm not doing a disservice. Any suggestions on how to make things clearer always welcome.

I'm working on allowing it to be a "drop in" replacement for RequireJS as well, still aiming to get the test coverage up a little more before announcing that properly though.

About your questions -

1. In theory it can support IE8+. The ES6 module polyfill works on IE8, but I would need to do a few IE8 function replacements (Array.prototype.indexOf etc) to properly get this support going. It shouldn't take more than an hour to get that up when the time comes though - create a ticket when you need it, and I'll get it done :)

2. The CDN is a convenience. It basically provides all of github and npm available without any install process necessary. The CDN is located at "https://github.jspm.io" and "https://npm.jspm.io". These CDNs then are created as "locations" by default in jspm (https://github.com/jspm/jspm-loader/blob/master/loader.js#L656).

This means I can write things like: jspm.import('npm:underscore');, which simply loads the URL https://npm.jspm.io/underscore.js, which then intelligently downloads the NPM module and gives back the latest version main file, with dependency management as well.

Does that make sense? Will think about how I can explain this better on the site.

[vanthome]

Hello Guy,

that sounds amazing!

You should clarify regarding the CDN

• Whether it is or will be a commercial offer
• Whether it just routes the requests to Github and npm or actually caches the resources
• Provide usage terms

As far as I understand the CDN machanism, I would be able to add my own one (programmatically)
If I had something like cdnjs -- is that right?

Again, I really really like this approach.

Cheers

[guybedford]

I actually just added cdnjs this morning - cdnjs/cdnjs#1728 (comment)

The CDN caches the resources, but regularly updates the cache so that there is never more than a minute delay (it is actually instant for new requests and a few seconds for branch updates). Exact version tag numbers are cached for longer than say the "master" branch request. It does all this quite intelligently.

The CDN costs money to run, but I am offering and always will offer it as a free service.

I have been thinking about whether or not to open source the CDN itself, but am undecided on this at the moment.

In terms of a commercial offering, I plan to provide a paid production service to pay for the free CDN. But I am first working on providing a completely open source build workflow using the jspm commandline tool that will work just as easily, exactly like the RequireJS optimizer. This way there is no lock in, as the self-hosting option will be simple and free just like standard builds today.

Would be interested to hear how that comes across though as well.