forest-books.js

const { collection } = require("forest-express-sequelize");

collection("books", {
  isSearchable: true,
  fields: [
    {
      field: "title",
      type: "String",
    },
    {
      field: "author",
      type: "Number", // this should be the type of the fk
      reference: "persons.id",
    },
  ],
});

forest-persons.js

const { collection } = require("forest-express-sequelize");

collection("persons", {
  isSearchable: true,
  fields: [
    {
      field: "firstname",
      type: "String",
    },
    {
      field: "lastname",
      type: "String",
    },
    {
      field: "books",
      type: ["Number"], // type should be an array of the type of the target pk
      reference: "books.id",
    },
  ],
});

routes-books.js

const { RecordSerializer } = require("forest-express-sequelize");
const express = require("express");
const router = express.Router();

const serializer = new RecordSerializer({ name: "books" });
const records = [
  {
    id: 1,
    title: "Foundation",
    author: { id: 1, firstname: "Isaac", lastname: "Asimov" },
  },
  {
    id: 2,
    title: "Beat the dealer",
    author: { id: 2, firstname: "Edward O.", lastname: "Thorp" },
  },
];

router.get("/books", async (req, res, next) => {
  const output = await serializer.serialize(records, { count: records.length });

  res.send(output);
});

router.get("/persons/:parentId/relationships/books", async (req, res, next) => {
  const related = records.filter(
    (r) => r.author.id === Number(req.params.parentId)
  );
  const output = await serializer.serialize(related, { count: related.length });

  res.send(output);
});

router.get("/books/:id", async (req, res, next) => {
  const record = records.find((r) => r.id === Number(req.params.id));
  const output = await serializer.serialize(record);

  res.send(output);
});

module.exports = router;

routes-persons.js

const { RecordSerializer } = require("forest-express-sequelize");
const express = require("express");
const router = express.Router();

const serializer = new RecordSerializer({ name: "persons" });
const records = [
  { id: 1, firstname: "Isaac", lastname: "Asimov" },
  { id: 2, firstname: "Edward O.", lastname: "Thorp" },
];

router.get("/persons", async (req, res, next) => {
  const output = await serializer.serialize(records, { count: records.length });

  res.send(output);
});

router.get("/persons/:id", async (req, res, next) => {
  const record = records.find((r) => r.id === Number(req.params.id));
  const output = await serializer.serialize(record);

  res.send(output);
});

module.exports = router;