How to push objects to an array in json-server with a database generated in JS?

Question

I have a json-server app running that generates the database on start dynamically with JS. The data I create is wrapped into a 'users' object as shown below:

{
    "users": [
        {
            "id": "user_id_0",
            "email": "[email protected]",
            "first_name": "Consuelo",
            "last_name": "Labadie",
            "last_login_time": 1638643810,
            "role": "Manager"
        },
        {
            "id": "user_id_1",
            "email": "[email protected]",
            "first_name": "Albina",
            "last_name": "Nienow",
            "last_login_time": 1637479536,
            "role": "User"
        }
    ],
    "Page": 1,
    "PageSize": 10,
    "Total": 10
}

I want to be able to push a new user into that array. Because I render my response to wrap it, if I just use the native POST, the request simply fails. So I want to write my own function for, but I can't figure out how to access and modify my created database?

How can I create a function to send data to my dynamically generated database?

Below are the rest of my files, in case it's of any use.

File: db.js

var faker = require('faker');
var utils = require('../utils.js');
const users_created = 10

module.exports = function () {
    const data = { users: [] }

    for (var i = 0; i < users_created; i++) {
        data.users.push({
            id: "user_id_" + i,
            email: faker.internet.email(),
            first_name: faker.name.firstName(),
            last_name: faker.name.lastName(),
            last_login_time: utils.string_to_oom_epoch(faker.date.recent(days = 40).toISOString().replace('Z', '')),
            role: faker.helpers.randomize(['Admin', 'Manager', 'User'])
        })
    }

    return data;
}

File: server.js

const jsonServer = require('json-server');
const server = jsonServer.create()
const router = jsonServer.router(require('./db.js')())
const middlewares = jsonServer.defaults()

server.use(middlewares)
server.use(jsonServer.bodyParser)

router.render = (req, res) => {
    if (req.url.startsWith('/generic_users_list')) {
            page = parseInt(req.query.page)
    pageSize = parseInt(req.query.pagesize)
    filter_email = req.query.email

    users = res.locals.data.users
    if (filter_email !== undefined) {
        filtered_users = []
        for (var i = 0; i < users.length; i++)
            if (users[i].email.toLowerCase() == filter_email.toLowerCase())
                filtered_users.push(users[i])
        users = filtered_users
    }

    if (!isNaN(pageSize)) {
        res.jsonp({
            users: users.slice(page * pageSize, (page + 1) * pageSize),
            Page: page,
            PageSize: pageSize,
            Total: users.length
        })
    } else {
        res.jsonp({
            users: users,
            Page: 1,
            PageSize: users.length,
            Total: users.length
        })
    }
    } else {
        res.jsonp(res.locals.data)
    }
}

server.post('/generic_users_list', (req, res) => {
    new_user = {
        id: req.body.id,
        email: req.body.email,
        first_name: req.body.first_name,
        last_name: req.body.last_name,
        last_login_time: req.body.last_login_time,
        role: req.body.role
    }
    // WHAT DO I HAVE TO DO HERE TO ADD 'new_user' TO MY DATABASE?
})

server.use(router)

server.listen(port = 3000, () => {
    console.log("port")
    console.log('JSON Server is running')
    console.log('http://localhost:' + port)
})

Tobi · Accepted Answer · 2021-12-23 16:09:22Z

1

You can extract the users array out of the export scope and define it as a constant. That way it lives in memory and you can add items to it. You just need to export another funtion, that may add a user to your in-memory database.

var faker = require('faker');
var utils = require('../utils.js');
const users_created = 10

const data = { users: [] }
let next_id = users_created;

function initDb() {
    for (var i = 0; i < users_created; i++) {
        data.users.push({
            id: "user_id_" + i,
            email: faker.internet.email(),
            first_name: faker.name.firstName(),
            last_name: faker.name.lastName(),
            last_login_time: utils.string_to_oom_epoch(faker.date.recent(days = 40).toISOString().replace('Z', '')),
            role: faker.helpers.randomize(['Admin', 'Manager', 'User'])
        })
    }

    return data;
}

function addUser(user) {
    user.id = "user_id_" + next_id++;
    data.users.push(user);
}

module.exports = {
    initDb,
    addUser,
    data
}

const jsonServer = require('json-server');
const server = jsonServer.create()
const user_db = require('./db.js')
const middlewares = jsonServer.defaults()

server.use(middlewares)
server.use(jsonServer.bodyParser)

user_db.initDb()
const router = jsonServer.router(user_db.data)

router.render = (req, res) => {
    if (req.url.startsWith('/generic_users_list')) {
            page = parseInt(req.query.page)
    pageSize = parseInt(req.query.pagesize)
    filter_email = req.query.email

    users = res.locals.data.users
    if (filter_email !== undefined) {
        filtered_users = []
        for (var i = 0; i < users.length; i++)
            if (users[i].email.toLowerCase() == filter_email.toLowerCase())
                filtered_users.push(users[i])
        users = filtered_users
    }

    if (!isNaN(pageSize)) {
        res.jsonp({
            users: users.slice(page * pageSize, (page + 1) * pageSize),
            Page: page,
            PageSize: pageSize,
            Total: users.length
        })
    } else {
        res.jsonp({
            users: users,
            Page: 1,
            PageSize: users.length,
            Total: users.length
        })
    }
    } else {
        res.jsonp(res.locals.data)
    }
}

server.post('/generic_users_list', (req, res) => {
    new_user = {
        id: req.body.id,
        email: req.body.email,
        first_name: req.body.first_name,
        last_name: req.body.last_name,
        last_login_time: req.body.last_login_time,
        role: req.body.role
    }
    user_db.addUser(new_user)
})

server.use(router)

server.listen(port = 3000, () => {
    console.log("port")
    console.log('JSON Server is running')
    console.log('http://localhost:' + port)
})

edited Dec 23, 2021 at 16:09

answered Dec 23, 2021 at 14:19

Tobi

6943 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Rodrigo Vaamonde Over a year ago

Not sure how this works, but trying to replicate your code I get: Error: Type of "initDb" (function) is not supported. Use objects or arrays of objects.

Tobi Over a year ago

Where are you using the initDb function?

Rodrigo Vaamonde Over a year ago

In the db.js file. Gets imported on server.js: const router = jsonServer.router(require('./db.js'))

Tobi Over a year ago

In my code I export an object. You would need to require it in a variable and destructure it. I updated my answer to provide complete code.

Rodrigo Vaamonde Over a year ago

I change my approach to building the database to yours and that solved my problem, thanks!

Collectives™ on Stack Overflow

How to push objects to an array in json-server with a database generated in JS?

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related