When you using 1st level $data's-property, it accessing to $data object directly through []-brackets
But you want to pass to selected-directive the path to nested object, so you should do something like this:
// source: https://stackoverflow.com/a/6842900/8311719
function deepSet(obj, value, path) {
var i;
path = path.split('.');
for (i = 0; i < path.length - 1; i++)
obj = obj[path[i]];
obj[path[i]] = value;
}
Vue.directive('selected', {
bind: function (el, binding, vnode) {
var select = $(el);
select.select2();
deepSet(vnode.context.$data, select.val(), binding.expression);
select.on('change', function () {
deepSet(vnode.context.$data, select.val(), binding.expression);
});
},
update: function (el, binding, newVnode, oldVnode) {
var select = $(el);
select.val(binding.value).trigger('change');
}
});
<select v-selected="userEditor.Id">
<option v-for="user in users" v-bind:value="user.id" >
{{ user.fullName}}
</option>
</select>
Description:
Suppose we have two $data's props: valOrObjectWithoutNesting and objLvl1:
data: function(){
return{
valOrObjectWithoutNesting: 'let it be some string',
objLvl1:{
objLvl2:{
objLvl3:{
objField: 'primitive string'
}
}
}
}
}
Variant with 1st level $data's-property:
<select v-selected="valOrObjectWithoutNesting">
// Now this code:
vnode.context.$data[binding.expression] = select.val();
// Equals to:
vnode.context.$data['valOrObjectWithoutNesting'] = select.val();
Variant with 4th level $data's-property:
<select v-selected="objLvl1.objLvl2.objLvl3.objField">
// Now this code:
vnode.context.$data[binding.expression] = select.val();
// Equals to:
vnode.context.$data['objLvl1.objLvl2.objLvl3.objField'] = select.val(); // error here
So the deepSet function in my code above "converting" $data['objLvl1.objLvl2.objLvl3.objField'] to $data['objLvl1']['objLvl2']['objLvl3']['objField'].
As you see, as I mentioned in comments to your question, when you want make select2-wrapper more customisable, the directive-way much more complicated, than separate component-way. In component, you would pass as much configuration props and event subscriptions as you want, you would avoid doing side mutations like vnode.context.$data[binding.expression] and your code would become more understandable and simpler for further support.
