Not possible to delete a child state object

[e2jk]

Assume an object's model defined as such:

module.exports = AmpersandModel.extend({
    props: {
        id: 'any',
        [snip]
    },
    children: {
      relatedSystem: System
    },

After an object has been saved with a child, at some point I want to remove that child. I would assume model.unset should do the job, but it results in an error (see below).
I have tried various strategies, none of which were succesful. What is the proper way to delete/remove a child item from a state object?

These were my intents, and the error message/code location where it failed:

Starting with the one I assumed would work (but apparently only works for actual properties and not children):

model.unset("relatedSystem");
model.save();

Results in TypeError: def is undefined at the if (def.required) line in the unset function, since this._definition only hold the real properties and not the children (is that on purpose?)

    unset: function (attrs, options) {
        attrs = Array.isArray(attrs) ? attrs : [attrs];
        forEach(attrs, function (key) {
            var def = this._definition[key];
            var val;
            if (def.required) {

Then trying to replicate what the unset function does when a property is not required (but without using the assign part because I was too lazy to figure out how to require lodash properly):

var val;
model.set("relatedSystem", val);
model.save();

That one doens't log any error, but going to that object's page (and properly refreshing) the child is still defined on the object.

Just trying to delete the object's property:

delete model.relatedSystem;
model.save();

Results in TypeError: this[key] is undefined at the third line in the serialize function:

    serialize: function () {
        var res = this.getAttributes({props: true}, true);
        forEach(this._children, function (value, key) {
            res[key] = this[key].serialize();
        }, this);

Another intent:

model.relatedSystem = {"systemName":"","vendorName":"","contactName":"","contactPhone":"","contactEmail":""};
model.save();

Results in TypeError: this[key].serialize is not a function on the same line as the previous error.

Last intent:

model.relatedSystem = {};
model.save();

Results in the same error as the previous intent.

[e2jk]

Hi there, any idea about how to remove a child from an object?

[e2jk]

Hi there, any thoughts about this issue?

[pgilad]

Sorry for the late response. You cannot unset a child as it's not a property, but an instance that belongs to the parent.
You could try using a state property type instead (which you could unset).
Another solution is to do:
model.set('relatedSystem', {})

and you could also try:
model.relatedSystem.unset()

If nothing works, could you add a failing test as a PR so that we may work a solution out? I feel that allowing to unset or empty a child should be allowed someway.

[pgilad]

@e2jk Did my comment help you solve your problem?