Add `createInstance` for resources with models

[kentcdodds]

I have this code:

    // All resources should be defined at this point
    var resourceNames = Object.keys(DS.definitions);
    // Add common meta data on all definitions
    angular.forEach(resourceNames, function(resourceName) {
      var definition = DS.definitions[resourceName];
      definition.meta = definition.meta || {};

      // add createInstance
      var ResourceClass = definition[definition.class] || Object;
      definition.meta.createInstance = function(attrs) {
        var instance = new ResourceClass();
        return angular.extend(instance, attrs);
      };
    });

This allows me to do this:

DS.definitions.user.meta.createInstance({
  id: 'SOME_RANDOM_ID',
  name: 'A Name',
  otherStuff: 324
});

Seems like this would be a common use case. Would be nice if it were baked in. What do you think?

[jmdobry]

So:

var user = DS.createInstance('user', attrs);

as sugar for:

var user = new DS.definitions.user[DS.definitions.user.class](attrs);

[kentcdodds]

👍 exactly

[jmdobry]

I like it.

[kentcdodds]

Hmmm, in trying to upgrade I ran into a snag with this solution. I have a function that takes a definition name, but sometimes that name is the plural form of the resource name (ie companies vs company) so what I do is attempt to get the definition from DS.definitions based on the singular version of what's given and then I have some custom mapping (like "toUser" is considered "user") as well to get the definition.

Adding createInstance on DS and requiring the definition name sort of breaks what I was trying to accomplish. So I think what I'll have to do is first identify the resource name based on whether there's a definition for what's given, and then I can use DS.createInstance with that resource name...

Thanks for letting me talk through this... I think I have a good solution, but it may have been nice to have createInstance on the definition as well... Just a thought :-)

[kentcdodds]

Just realized this is in version 0.10.1, and there's no tag for that yet. So I can't use it quite yet. But that's ok because it allows you to make this change easier (if that's something you want to do). What do you think?

[jmdobry]

Adding createInstance on DS and requiring the definition name

This was my original proposal, but I can add a method on the resource definition that wraps the DS.createInstance call. In fact, it might be nice for the resource definition object to wrap all DS methods that require a resource name. I'll change defineResource to return the definition object (it should have done that already). e.g.:

var User = DS.defineResource({ name: 'user', ... });

User.find(5).then(...); // Same as DS.find('user', 5)
User.findAll({...}).then(...); // Same as DS.findAll('user', {...})
User.get(5); // Same as DS.get('user', 5)
User.filter({...}); // Same as DS.filter('user', {...})
User.createInstance({...}); // Same as DS.createInstance('user', {...})

[kentcdodds]

Yeah, I didn't realize that your proposal wouldn't work with how I implemented it. But I got around it pretty easily.

That solution actually sounds amazing. I think it would make things easier to work with.