loopback parent model - how to set properties and create child models

Question

I have several loopback models and I want to add shared functions to them. I'm not really sure if I understand loopback's extend approach, but I created a Dictionary model, set other models base property to Dictionary and got stuck here.

Essentially I need to create an instance of child model, fetch some data and build a hash. Then I plan to call app.models.ChildModel.createHash() several times in the boot script to create dictionary for each of the models.

I'm not sure where to start.. how do I pass the child class name (or instance) to parent? I obviously need it to query the data.

I made a working solution for a concrete Regions model

module.exports = function(Regions){
var countriesHash={};
Regions.setup=function(next){
    Regions.find({where:{type:'Country'}}, function(err, countries){
        countries.forEach(function(country){
            countriesHash[country.id]=country;
        });
        console.log('hash built');
        next();
    });
};

but I want to refactor it to abstract Dictionary class and just set a few properties like child name and where in concrete models.

Answer 1

You can use mixin (here) to put shared functionalities there and use in models.

Also you can send them some options.