how to implement mutation responses on a local falcor Model dataset - falcor

Question

Given that I have an example Model:
var model = new falcor.Model({
cache: {
userById: {
"1": {
name: "User",
email: "user#email.com"
}
},
users: {
current: null
}
}
});
This is a local model that I'm using for testing purposes, and I would like to implement it on a call to users.login so the user so that I can call:
model.call(['users', 'login'], ['user', 'password'])
I realized that if I do this:
var model = new falcor.Model({
cache: {
userById: {
"1": {
name: "User",
email: "user#email.com"
}
},
users: {
current: null,
login: function(user, password) {
console.log('this code is reached', user, password);
// what to return in order to mutate model?
}
},
}
});
When I do the call it gets there, but I can't figure out how to mutate the model as part of the response; on the server side we return the paths with values and invalidates, and it just works, but here I tried:
// trying returning as a jsonGraph response, don't work
login: function() {
return {
jsonGraph: {
users: {
current: {$type: "ref", value: ['userById', '1']}
}
},
paths: [['users', 'current']]
}
}
// trying returning as a path set mutation list, don't work
login: function() {
return [{path: ['users', 'current'], value: {$type: "ref", value: ['userById', '1']}}]
}
// trying force call to set on the model, don't work
login: function() {
this.set([
{path: ['users', 'current'], value: {$type: "ref", value: ['userById', '1']}}
])
}
// trying using ModelResponse, got an example on some external sources, don't work
login: funtion() {
return new ModelResponse((observer) => {
observer.onNext({
jsonGraph: {
users: {
current: {$type: "ref", value: ['userById', '1']}
}
},
paths: [['users', 'current']]
});
observer.onCompleted();
});
}
Now I don't know what else to try; I need a simple way to declare mutations after a call into a local model, if you know how to solve this, please let me know here.
Thanks.

Answer 1

The client model cache only supports JSONGraph, which b/c it is essentially just JSON with some conventions, doesn't support functions. So, when working with a falcor model cache and no dataSource/middle tier router, it is not possible to implement calls.
This can be kind of annoying when prototyping/testing, as a router is conceptually more difficult than a simple JSON cache object. I ran into this a while ago, so I wrote a dataSource module to support it: falcor-local-datasource. The dataSource is initialized with a graph object that does support function nodes, and as with your above examples, will mutate the graph based on the function's returned JSONGraphEnvelope or an array of PathValues.