wasm-experiments/README.md

wasm-experiments

Just some playing around with the experimental Go WebAssembly arch target.

Requirements

Requires go >= 1.13.0. TinyGo examples require docker.

Basic instructions

Choose your target from the experiments. Compile with make <target> and serve with make serve. This starts a local web server which serves the ./html directory. It ensures .wasm files are served with their appropriate content-type.

For example:

$ make hello
rm -f ./html/*
GOOS=js GOARCH=wasm go build -o ./html/test.wasm ./hello/main.go
cp $(go env GOROOT)/misc/wasm/wasm_exec.html ./html/index.html
cp $(go env GOROOT)/misc/wasm/wasm_exec.js ./html/wasm_exec.js
$ go run main.go
2019/02/24 14:11:51 Serving on http://localhost:8080

Navigate to http://localhost:8080 to load the page. Some examples require opening the browser console to be seen.

Gzip compression

Use the -gzip flag to enable on-the-fly gzip compression of the files:

$ go run main.go -gzip
2019/02/24 14:11:51 Serving on http://localhost:8080

TinyGo targets

To compile something with the TinyGo WebAssembly compiler, simply choose the target and invoke the tinygo make rule with the target specified and serve as usual. For example:

$ make tinygo target=hello
docker run --rm -v $$(pwd):/go/src/github.com/johanbrandhorst/wasm-experiments tinygo/tinygo:0.8.0 /bin/bash -c "\
        cd /go/src/github.com/johanbrandhorst/wasm-experiments && \
        tinygo build -o ./html/test.wasm -target wasm --no-debug ./hello/main.go && \
        cp /usr/local/tinygo/targets/wasm_exec.js ./html/wasm_exec.js\
"
cp $$(go env GOROOT)/misc/wasm/wasm_exec.html ./html/index.html
sed -i -e 's;</button>;</button>\n\t<div id=\"target\"></div>;' ./html/index.html
$ go run main.go
2019/02/24 14:33:58 Serving on http://localhost:8080

Note that some of the targets either do not compile or panic at runtime when compiled with TinyGo. The following targets have been tested to work with TinyGo:

• hello
• channels
• js
• tinygo-canvas

Experiments

Hello

A simple Hello World example that prints to the browser console.

Channels

Showing basic first class support for channel operations in compiled WebAssembly.

JS

A simple example of how to interact with the JavaScript world from WebAssembly.

Fetch

A more complicated example showing how to use net/http DefaultClient to send a HTTP request, parse the result and write it to the DOM.

Canvas

An updated version of the repulsion demo by Luis Figuerido.

TinyGo-Canvas

Same as above but built with TinyGo.

Ebiten

A short demo of using the Ebiten game engine to create a WebGL based flappy bird clone. Copied from the Ebiten examples.

Vugu

An example of a Vugu application reading the latest bitcoin price.

Vecty

An example of a Vecty application automatically translating the input textbox to rendered markdown.

Export

An example of exporting a Go function to JavaScript.