# JS Framework

## Core Interfaces

### JSValue

Base interface for any JavaScript value. Provides type-safe access to underlying values.

```go
package jsframe

import "reflect"

type JSValue interface {
    GoType() reflect.Type
    GoValue() reflect.Value

    SliceValues() ([]JSValue, bool)
    MapValues() (map[string]JSValue, bool)
}
```

**Methods:**

- `GoType()` - Returns the Go `reflect.Type` of the underlying value
- `GoValue()` - Returns the underlying Go value
- `SliceValues()` - Returns `(values, true)` if the value is a slice/array, `(nil, false)` otherwise
- `MapValues()` - Returns `(values, true)` if the value is an object/map, `(nil, false)` otherwise

---

### JSCallable

Interface for callable values (functions). Extends `JSValue` by adding call semantics and type information.

```go
type JSCallable interface {
    JSValue

    ArgumentTypes() []TypeInfo
    ReturnType() TypeInfo

    Call(ctx Context, args ...JSValue) (JSValue, error)
}
```

**Methods:**

- `Call(ctx, args)` - Executes the function with provided arguments. Returns a JSValue and an error. The framework converts errors to JavaScript exceptions.
- `ArgumentTypes()` - Returns type information for each argument
- `ReturnType()` - Returns type information for the return value

## Callable / Builtin Registrar

```go
type BuiltinFunc[T any, R any] func(args T) (R, error)

type BuiltinArgs[T any] interface {
    T
    Defaults() T
}

func RegisterBuiltin[T any, R any](name string, fn BuiltinFunc[T, R]) JSCallable
```

## Goja Types <-> Go Types Converstion

Implement bidirectional conversion between goja values and go values.