app.js

const jsonServer = require("json-server")

const films = require("./films.json")
const people = require("./people.json")
const planets = require("./planets.json")
const species = require("./species.json")
const starships = require("./starships.json")
const transport = require("./transport.json")
const vehicles = require("./vehicles.json")

const db = {
  films,
  people,
  planets,
  species,
  starships,
  transport,
  vehicles,
}

/**
 * Lifting the "fields" to the root of the object
 * Using the "pk" as the "id"
 */
const fdb = Object.keys(db).reduce((acc, current) => {
  acc[current] = db[current].map(item => {
    return Object.assign(item.fields, {
      id: item.pk,
    })
  })

  return acc
}, {})

/**
 * Vehicles and Starships "extend" Transport...
 */

const xdb = Object.keys(fdb).reduce((acc, current) => {
  if (current === "starships" || current === "vehicles") {
    acc[current] = acc[current].map(item => {
      const transport = acc["transport"].find(elm => {
        return elm.id === item.id
      })

      if (transport) {
        return Object.assign(item, transport)
      }

      return item
    })
  }
  return acc
}, fdb)

/**
 * Relation definitions to match them with swapi.co
 */
const relations = [
  {
    name: "people",
    relation: [
      {
        alias: "vehicles",
        table: "vehicles",
        name: "pilots",
        type: Array,
      },
      {
        alias: "starships",
        table: "starships",
        name: "pilots",
        type: Array,
      },
      {
        alias: "films",
        table: "films",
        name: "characters",
        type: Array,
      },
    ],
  },
  {
    name: "planets",
    relation: [
      {
        alias: "residents",
        table: "people",
        name: "homeworld",
        type: Number,
      },
      {
        alias: "films",
        table: "films",
        name: "planets",
        type: Array,
      },
    ],
  },
  {
    name: "starships",
    relation: [
      {
        alias: "films",
        table: "films",
        name: "starships",
        type: Array,
      },
    ],
  },
]

function addRelation(db, host, relations) {
  return relations.reduce((acc, relation) => {
    const alias = relation.alias
    const table = relation.table
    const name = relation.name
    if (relation.type === Number) {
      acc[alias] = db[table]
        .filter(item => item[name] === host.id)
        .map(item => item.id)

      return acc
    }

    acc[alias] = db[table]
      .filter(item => item[name].indexOf(host.id) > -1)
      .map(item => item.id)

    return acc
  }, {})
}

const relationDb = relations.reduce((acc, current) => {
  acc[current.name] = acc[current.name].map(item => {
    return Object.assign(
      item,
      addRelation(acc, item, current.relation)
    )
  })
  return acc
}, xdb)

const server = jsonServer.create()

const serveStatic = require("serve-static")
const path = require("path")
server.use(
  serveStatic(path.join(__dirname, "public"), {
    maxAge: "1d",
  })
)

server.use((req, res, next) => {
  const { delay } = req.query

  if (delay) {
    setTimeout(() => {
      next()
    }, Number(delay))
  } else {
    next()
  }
})

server.use(jsonServer.defaults())

const router = jsonServer.router(relationDb)
server.use(router)

server.listen(process.env.PORT || 3000)
console.log(`Server started on port 3000`)