// Wrap returns a wrapper func that handles the conversion from native JavaScript *js.Object parameters
// to the following types.
//
// It supports *js.Object (left unmodified), dom.Document, dom.Element, dom.Event, dom.HTMLElement, dom.Node.
//
// For other types, the input is assumed to be a JSON string which is then unmarshalled into that type.
func Wrap(fn interface{}) func(...*js.Object) {
v := reflect.ValueOf(fn)
return func(args ...*js.Object) {
in := make([]reflect.Value, v.Type().NumIn())
for i := range in {
switch t := v.Type().In(i); t {
// *js.Object is passed through.
case typeOf((**js.Object)(nil)):
in[i] = reflect.ValueOf(args[i])
// dom types are wrapped.
case typeOf((*dom.Document)(nil)):
in[i] = reflect.ValueOf(dom.WrapDocument(args[i]))
case typeOf((*dom.Element)(nil)):
in[i] = reflect.ValueOf(dom.WrapElement(args[i]))
case typeOf((*dom.Event)(nil)):
in[i] = reflect.ValueOf(dom.WrapEvent(args[i]))
case typeOf((*dom.HTMLElement)(nil)):
in[i] = reflect.ValueOf(dom.WrapHTMLElement(args[i]))
case typeOf((*dom.Node)(nil)):
in[i] = reflect.ValueOf(dom.WrapNode(args[i]))
// Unmarshal incoming encoded JSON into the Go type.
default:
p := reflect.New(t)
err := json.Unmarshal([]byte(args[i].String()), p.Interface())
if err != nil {
panic(err)
}
in[i] = reflect.Indirect(p)
}
}
v.Call(in)
}
}
func (w *WidthAnimator) Apply(item interface{}) {
obj, ok := item.(*js.Object)
if !ok {
return
}
domNode := dom.WrapHTMLElement(obj)
styles := domNode.Style()
w.cache = append(cachable{
item: domNode,
value: styles.GetPropertyValue("width").Int(),
})
}