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Nick Marsceau

Compiling Go to Web Assembly in PowerShell

Posted on

this-week-i-learned go web-assembly powershell

I've been learning Go lately, and I wanted to experiment with web assembly as well. I whipped up an example that will pass a user-specified message to a WASM function, which will return a JSON object containing the value it received.

Screenshot of my sample web assembly web page. I entered the value 'Hello World'.Another screenshot of my sample web assembly web page. I clicked the button, and the browser alerted the JSON object it received from the web assembly function.

The command for compiling Go to web assembly without any tools like TinyGo is this:


GOOS=js GOARCH=wasm go build -o "./path/to/output/file.wasm" "./path/to/source/file.go"

That syntax works for Bash (and probably other Linux-based shells like Zsh, etc.), but I currently use PowerShell as my primary shell. I learned from this StackOverflow thread what the correct syntax for setting environment variables in PowerShell is:


$env:GOOS = 'js'; $env:GOARCH = 'wasm'; go build -o "./path/to/output/file.wasm" "./path/to/source/file.go"

For convenience, I wrote a PowerShell function to encapsulate that command:

This function sets the environment variables and compiles the code in a child process or "subshell" so the variables don't overwrite any that may already be set in the current shell. Place this function in your PowerShell profile to use it.