Function MakeFunc

compiler/natives/src/reflect/reflect.go:355–400

gopherjs:replace

(typ Type, fn func(args []Value) (results []Value))

//gopherjs:replace
func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value {
	if typ.Kind() != Func {
		panic("reflect: call of MakeFunc with non-Func type")
	}

	t := typ.common()
	ftyp := (*funcType)(unsafe.Pointer(t))

	fv := js.MakeFunc(func(this *js.Object, arguments []*js.Object) any {
		// Convert raw JS arguments into []Value the user-supplied function expects.
		args := make([]Value, ftyp.NumIn())
		for i := range args {
			argType := ftyp.In(i)
			args[i] = makeValue(argType, arguments[i], 0)
		}

		// Call the user-supplied function.
		resultsSlice := fn(args)

		// Verify that returned value types are compatible with the function type specified by the caller.
		if want, got := ftyp.NumOut(), len(resultsSlice); want != got {
			panic("reflect: expected " + strconv.Itoa(want) + " return values, got " + strconv.Itoa(got))
		}
		for i, rtyp := range ftyp.OutSlice() {
			if !resultsSlice[i].Type().AssignableTo(toRType(rtyp)) {
				panic("reflect: " + strconv.Itoa(i) + " return value type is not compatible with the function declaration")
			}
		}

		// Rearrange return values according to the expected function signature.
		switch ftyp.NumOut() {
		case 0:
			return nil
		case 1:
			return resultsSlice[0].object()
		default:
			results := js.Global.Get("Array").New(ftyp.NumOut())
			for i, r := range resultsSlice {
				results.SetIndex(i, r.object())
			}
			return results
		}
	})

	return Value{t, unsafe.Pointer(fv.Unsafe()), flag(Func)}
}

//gopherjs:replace
func typedmemmove(t *abi.Type, dst, src unsafe.Pointer) {