72 lines
1.6 KiB
Markdown
72 lines
1.6 KiB
Markdown
# go-promises
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Return promises from Go WASM.
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## Usage
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Write some go code, like this.
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```go
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import (
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"syscall/js"
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promises "codeberg.org/danjones000/go-promises"
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)
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func Add(a, b int) int {
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return a + b
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}
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func AddWrapper() value.JSWrapper {
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return func(this js.Value, args []js.Value) (any, error) {
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if len(args) < 2 {
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return nil, errors.New("add called with too few arguments")
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}
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a := args[0]
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b := args[1]
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if a.Type() != js.TypeNumber {
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return nil, fmt.Errorf("First argument must be a number. %s given", a.Type())
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}
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if b.Type() != js.TypeNumber {
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return nil, fmt.Errorf("secong argument must be a number. %s given", b.Type())
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}
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return Add(a.Int(), b.Int()), nil
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}
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}
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func main() {
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js.Global().Set("add", promises.PromisifyGoFunc(AddWrapper()))
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<-make(chan struct{})
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}
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```
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Next, compile this code:
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```shell
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GOOS=js GOARCH=wasm go build -o ./app.wasm ./
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```
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Copy the `app.wasm` file, as well as the `wasm_exec.js` from your go installation, into wherever you have your web files located.
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```shell
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cp app.wasm "$(go env GOROOT)"/misc/wasm/wasm_exec.js path/to/web/
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```
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Finally, you'll need some frontend code like this:
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```javascript
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const go = new Go();
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WebAssembly.instantiateStreaming(fetch("app.wasm"), go.importObject).then((result) => {
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go.run(result.instance);
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});
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```
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Now, the "add" function is available anywhere in your javascript.
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## Roadmap
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- [ ] Argument validation, so you can write less code in your wrapper function.
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- [ ] An easy method for attaching functions to other objects, so they don't have to be in the global scope
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