How to generate struct methods to frontend in this case?

[KiddoV]

Why is my generated JS class doesn't come with my struct method in this case?

I have a every basic struct:

package test

type TestStruct struct {
    Field1 string
    Field2 int
}

func (t *TestStruct) SomeMethod() error {
    fmt.Println("TestStruct.SomeMethod() called!")
    return nil
}

I have a function to init this struct in the main app struct:

package main

func (a *App) NewTestStruc() *test.TestStruct {
    return &test.TestStruct{}
}

---

Now in the frontend I call the function to init the struct:

import { NewTestStruc } from 'wailsjs/go/main/App';
import { test } from 'wailsjs/go/models';

[...]
var testStructFE: test.TestStruct;

NewTestStruc().then(st => {
    testStructFE = st;
    //Now my `testStructFE` var doesn't come with any methods
}).catch(() =>{});

However I don't see any struct methods created in the models.ts with class test in my frontend.

Is it even possible for Wails?

[KiddoV]

Answer in https://discord.com/channels/1042734330029547630/1061396491769479300/1217547615537729688
I don't think it is possible.

[leaanthony]

Is it because you don't have json tags?

[KiddoV]

I do have all of my JSON tags in the struct fields; the code provided was just a minimal example of my actual code. However, I've never placed my struct instance directly in the Bind. Instead, I intended to instantiate it within an app method, store it in a JavaScript variable, and then call its methods from the frontend. I've come to realize that in Wails, I only have two options:

1. Instantiate a struct instance first in Go side and include it in the Bind to expose all its methods in the frontend (though its struct fields wont be exposed), or
2. Bind the struct to the frontend via an app method to access the struct fields (as a class type in JavaScript, but without its methods).

There is noway to get both (the struct fields and methods as a class in JS)

[geocine]

@KiddoV you can use Bind on wails.Run . You may check https://wails.io/docs/guides/application-development/#dealing-with-context-when-binding-multiple-structs

Your struct

package test

type TestStruct struct {
    Field1 string
    Field2 int
}

func (t *TestStruct) SomeMethod() error {
    fmt.Println("TestStruct.SomeMethod() called!")
    return nil
}

func NewTestStruc() *TestStruct {
    return &TestStruct{}
}

Then on your app.go

package main

import (
	"yourpkg/test"
)

type App struct {
	ctx context.Context

	TestStruct *TestStruct
}

func NewApp() *App {

	app := &App{
		TestStruct: test.NewTestStruc(),
	}
	
	return app
}

Then on you main.go

func main() {
	// ....
	app := NewApp()

	// Create application with options
	err := wails.Run(&options.App{
		// ....
		Bind: []interface{}{
			app,
			app.TestStruct, // Your Struct
		},
	})
}

This should generate

wails/go/test/TestStruct

[KiddoV]

Thanks for the answer, but as I said earlier in 1. If you do this, you can only get the struct methods generated, without the struct fields exposed in the frontend.

I would expected to see something like this in frontend:
wails/go/test/.. or wails/go/models

export class TestStruct {
    //The struct fields...
    field1: string;
    field2: number;
    
    [...]
    //...Then the method:
    SomeMethod(): Promise<void>;
}

However, I was mistaken. This isn't possible in Wails, or at least not how Wails binding generation works.
You can only instantiate a struct instance in the backend then exposed its methods to frontend via &options.App.Bind (without its struct fields as an exported class). Or you can use the struct as a type for some method in backend, and it will automatically generate exported class in the frontend (without its methods).

[geocine]

Right I just noticed, it doesn't export its as a class but a module.