NodeJS: how to implement repository pattern - node.js

Question

I would like to implement the Repository pattern in my NodeJS app, but I'm running into troubles with circular requires (I guess...).
How I'm trying to implement it:
PersonRepository class with methods: getAll, getById, create, update, delete
Person class with methods: init, createAccount, showRelations, addRelation,
First of all: Is my repository pattern design correct?
My classes:
personRepository.js
const PersonModel = require('./model');
const Person = require('./person');
class PersonRepository {
constructor() {
this._persons = new Set();
}
getAll( cb ) { // To Do: convert to promise
let results = new Set();
PersonModel.find({}, 'firstName lastName', (err, people) => {
if (err) {
console.error(err);
}
people.forEach((person, index) => {
let foundPerson = new Person(person._id.toString(), person.firstName, person.lastName, person.email, person.birthday);
results.add(foundPerson);
});
this._persons = results;
if (cb) cb(this._persons);
});
}
getById(id) {
return PersonModel.findOne({ _id: id });
}
getByEmail(email) {
throw new Error("Method not implemented");
}
create( person ) {
throw new Error("Method not implemented");
}
update ( person ) {
throw new Error("Method not implemented");
}
delete ( person ) {
throw new Error("Method not implemented");
}
}
module.exports = new PersonRepository();
person.js
const PersonModel = require('./model');
const personRepository = require('./personRepository');
class Person {
constructor(personId, first, last, email, birthday) {
this._id = personId ? personId : undefined;
this._firstName = first ? first : undefined;
this._lastName = last ? last : undefined;
this._email = email ? email : undefined;
this._birthday = birthday ? new Date(birthday) : undefined;
this._relations = new Map();
}
init() { // Get all data from database
personRepository.getById(this._id)
.then(console.log)
.catch(console.error);
}
}
module.exports = Person;
tests.js
console.log("--- GET ALL : results--- ");
personRepository.getAll( (persons) => {
for (let person of persons) {
person.loadAllData()
.then(() => {
console.log(person);
})
.catch((e) => {
console.log(e);
});
}
});
console.log("--- INIT : results--- ");
var personInit = new Person("59c18a9029ef510012312995");
console.log("before init");
console.log(personInit);
personInit.init();
console.log("after init");
console.log(personInit);
Problem:
When running the "Get all" test (without the INIT tests), it works.
When I add the INIT tests, I get the error:
personRepository.getById(this._id)
^
TypeError: personRepository.getById is not a function
at Person.init
How can I prevent this from happening?
- Change the way I require my modules?
- Change my design? (eg. don't require Person class in personRepository and just create a Set of ids in "getAll" instead of a Set of persons)
- Other ideas?
Thanks for helping me! I'm trying to solve this for hours now...

Answer 1

Solved it myself. The problem was a circular dependency between the 2 modules. Problem is fixed by moving the requires after the module.exports.
Reference: https://coderwall.com/p/myzvmg/circular-dependencies-in-node-js