play

2020 Update

• The compile.jsgo.io and play.jsgo.io services have been shut down.
• Anything deployed to jsgo.io or pkg.jsgo.io will continue to work fine.

I created the jsgo.io system several years ago, and it costs about $150/month to host which I pay personally. I'm tightening up my finances right now, so this outgoing had to stop.

If anyone would like to host it for me (it runs on a single GKE n1-standard-2 instance), please let me know and we can get it back online!

I had a plan for a big rewrite that would make is possible to run on App Engine, thus reduce the cost to almost zero. Unfortunately this is something I'm hesitant to start, because it seems that Go on the client is moving away from GopherJS and towards WASM.

play.jsgo.io

Edit and run Go in the browser, supporting arbitrary import paths!

https://play.jsgo.io/

The jsgo playground is an extension of the jsgo compiler. The compiler allows you to easily compile Go to JS using GopherJS, and automatically host the results in an aggressively cached CDN. The playground adds an online editor and many other features (see below).

The unique feature of the jsgo playground is that it supports arbitrary import paths. Other Go playgrounds are limited to just the Go standard library.

For more for more info:

• jsgo compiler: https://github.com/dave/jsgo
• jsgo playground: https://github.com/dave/play

Demos

Here's the simplest demo - it just writes to the console and to the page:

• https://play.jsgo.io/github.com/dave/jstest

Here's a couple of simple demos that accept files by drag and drop. The first compresses dropped files to a zip. The second compresses images to jpg. They use the Go standard library zip / image libraries, which work flawlessly in the browser:

• https://play.jsgo.io/github.com/dave/zip
• https://play.jsgo.io/github.com/dave/img

The amazing ebiten 2D games library is a perfect example of the power of Go in the browser. Here's some demos:

• https://play.jsgo.io/github.com/hajimehoshi/ebiten/examples/2048
• https://play.jsgo.io/github.com/hajimehoshi/go-inovation
• https://play.jsgo.io/github.com/hajimehoshi/ebiten/examples/flappy

Contact

If you'd like to chat more about the project, feel free to add an issue, mention @dave or post in the #gopherjs channel of the Gophers Slack. I'm happy to help!

Features

Initialise

The URL can be used to initialise with code in several ways:

• Load a Go package with /{{ Package path }}
• Load a Github Gist with /gist.github.com/{{ Gist ID }}
• Load a shared project with /{{ Share ID }}
• Load a play.golang.org share with /p/{{ Go playground ID }}

Run

Click the Run button to run your code in the right-hand panel. If the imports have been changed recently, the dependencies will be refreshed before running.

Format code

Use the Format code option to run gofmt on your code. This is executed automatically when the Run, Update, Share or Deploy features are used.

Update

If you update a dependency, use the Update option, which does the equivalent of go get -u and refreshes the changes in any import or dependency.

Share

To share your project with others, use the Share option. Your project will be persisted to a json file on src.jsgo.io and the page will update to a sharable URL.

Deploy

To deploy your code to jsgo.io, use the Deploy feature. A modal will be displayed with the link to the page on jsgo.io, and the Loader JS on pkg.jsgo.io.

Use the jsgo.io link for testing and toy projects. Remember you're sharing the jsgo.io domain with everyone else, so the browser environment should be considered toxic.

The Loader JS on pkg.jsgo.io can be used in production, and should be added to a script tag on your own website. See github.com/dave/jsgo for more information.

Console

Writes to os.Stdout are redirected to a playground console, which can be toggled using the Show console option. The console will automatically appear the first time it's written to.

Minify

In normal usage, all JS is minified. For debugging, this can be toggled with the Minify JS option.

Build tags

The build tags used when compiling can be edited with the Build tags... option. The selected build tags are persisted when using the Share feature.

Download

The Download option downloads the project. Single file projects are downloaded as a single file, while multi-file projects download as a zip.

Upload

Files can be uploaded to the project simply by drag+drop. Zip files generated by the Download feature can be uploaded to restore a multi-file project.

File menu

Change the selected file with the file menu.

Add file

Add a file to the current package with the Add file option. Only .go, .md and .inc.js files are supported. If no extension is supplied, .go is added.

Delete file

Delete a file from the current package with the Delete file option.

Package menu

Change the selected package with the package menu.

Add package

Add an empty package with the Add package option.

Load package

The source for an import or dependency can be loaded with the Load package option. By default, only the direct imports of your project are listed. Use the Show all dependencies option to show the entire dependency tree.

Remove package

A package can be removed with the Remove package option.

Run locally?

If you'd like to run play.jsgo.io locally, take a look at these instructions.