“A language a year keeps the doc away!”

The famous block game written in Go compiled to WASM. It is a quick port from TypeTris.

Play it! Main source code Download ZIP


Use cursor keys SPACE or I J K L M SPACE to control the game.

You need a recent version of Chrome, Firefox, (non-legacy) Edge or Safari to play it.


Use build.sh to build it.

Go version 1.14 is needed because of WASM support. Although syscall/js is available from 1.11 on. However the backward compatibility promise does not applies to this package (fortunately, because there was some major simplification between 1.11 and 1.14). This implies that the code may be broken in versions other then 1.14. I try to keep this up-to-date.

What did I learn?

I learned to love channels again!

Debugging was - due to the absence of tools - not a breeze, but the good thing is that the Golang logger logs to the browser console and in case of errors full stack traces are available in the console too.


Also this was my first real WASM project. To make this portable I abstracted the renderer (browser.go) and it is desired to do this for the keyboard handler too.

Golang package size

The resulting WASM binary is ~1.5 MB (gzipped: 460 KB). I used these packages:

package size
log ~400 KB
math/rand ~20 KB
time ? KB (to be measured)

I omitted the log file from the production version so it saves some bytes. Omitting the math/rand packages was not worth it. If you really want you can use something like date.Nanoseconds % len(blocks) to get a random block. Maybe give TinyGo a go for a smaller WASM file?

Source code

Name Description Last modified Size
blocks.go Golang 13 March 1.6 KBDownload
browser.go Golang 16 March 2.5 KBDownload
build.sh Shell script 15 March 178 BytesDownload
gotris-big.png PNG image 16 March 12.1 KBDownload
gotris-small.png PNG image 13 March 6.0 KBDownload
gotris.css Stylesheet 19 March 103 BytesDownload
gotris.go Golang 16 March 4.6 KBDownload
gotris.html HTML 19 March 468 BytesDownload
gotris.js JavaScript 15 March 817 BytesDownload
gotris.png PNG image 16 March 12.1 KBDownload
gotris.wasm WASM binary 16 March 1.5 MBDownload
gotris.zip Zip archive 16 March 474.4 KBDownload
render.go Golang 16 March 180 BytesDownload
tetris.css Stylesheet Oct ’17 2.8 KBDownload
wasm_exec.js JavaScript 16 March 16.9 KBDownload
15 files 2.0 MB