hemae/field-database

fieldDB object modeling for node.js

field-database

fieldDB object modeling for node.js

Table of contents

• Features
• Installing
• Example
  • Model creation
  • Connection
  • Usage
  • Available methods
    • save
    • find
    • findById
    • findOne
    • findByIdAndUpdate
    • findByIdAndDelete
• Errors

Features

• creation of custom classes (models) for the production of the required objects according to a pre-specified scheme
• validation of created objects by type, need for data availability, existence of declared keys (setting when creating a model)

Installing

Add the package to your project

npm i filed-database

Example

Model creation

To create model that will be used in you project, use function Model provided by field-database
Export last one:

const {FieldDocumentType, Model} = require('field-database')

const schema = {
    messageText: {type: 'string', required: true},
    date: {type: 'number', required: true},
    note: {type: 'string', default: null},
    deleted: {type: 'boolean', default: false},
    likes: {type: 'object', default: []}
}

const Message = Model('message', schema)

export default Message

using TypeScript:

import {FieldDocumentType, Model} from 'field-database'


export type MessageType = FieldDocumentType & {
    messageText: string
    date: number
    note: string | null
    deleted: boolean
    likes: Array<string>
}

const schema = {
    messageText: {type: 'string', required: true},
    date: {type: 'number', required: true},
    note: {type: 'string', default: null},
    deleted: {type: 'boolean', default: false},
    likes: {type: 'object', default: []}
}


const Message = Model<MessageType>('message', schema)

export default Message

When we create a schema for the model, we may specify type, require and default parameters.
type may be:

• 'number'
• 'string'
• 'boolean'
• 'object' (arrays, objects and null)

type is required in schema, other are optional. Default value of required is false, for default is undefined

---

Connection to database

!Before connecting to database, make you sure you have network connection!
Using express (TypeScript):

import {Express} from 'express'
const express = require('express')
import field from 'field-database'

const app: Express = express()
const PORT: number = 5000
async function start() {
    try {
        await field.connect({
            login: 'test',
            password: '111111',
            projectId: 'Project ID'
        })
        console.log('FieldDB is connected')
        app.listen(PORT, () => log.info(`Server has been started on port ${PORT}`))
    } catch (e: any) {
        console.log(`Server Error: ${e.message}`)
        process.exit(1)
    }
}

start()

---

Usage

Continuing with the example above, using express router. Here we create new instance providing initial parameters. Method save makes corresponding records in database.

import Message from '../models/Message'
const router: IRouter = Router()

router.put('/',
    async (req, res) => {
        try {
            const {messageText} = req.body as {messageText: string}
            const message = new Message({
                messageText,
                date: Date.now()
            })
            await message.save()
            res.json({message})
        } catch (e: any) {
            log.error(e.message)
            res.status(500).json({message: 'Something went wrong'})
        }
    }
)

If we try to look what object message is, we can see:

{
    _id: 'some id',
    _creationDate: 1637876142324,
    _updatingDate: null,
    messageText: 'some message text',
    date: 1637876142324,
    note: null,
    deleted: false,
    likes: []
}

---

Available methods

Demo version of the database make available following asynchronous methods

save

save is instance method. It saves object record in database and returns a Promise without payload (void)

await message.save()

find

find is static method. It returns a Promise with array payload:

// we can use this method without any parameters
// and get all objects from collection with model Message
const messages = await Message.find()
// as well as with object parameter named filter
// in this case we will get only objects according to filter value
const ownerMessages = await Message.find({ownerId: 'some id of owner'})

// filter can be compound
const ownerDeletedMessages = await Message.find({ownerId: 'some id of owner', deleted: true})

findById

findById is static method. It returns a Promise with object or null payload:

// we should to provide only one parameter: id
const message = await Message.findById('some message id')
// if database find corresponding object we get object, else: null

findOne

findOne is static method. It returns a Promise with object or null payload like findById

// but now we should to provide any filter instead of id
const message = await Message.findById({messageText: 'This is message'})
// in this case we get the first found object with field 'messageText' equal to 'This is message'
// or null if object not found

findByIdAndUpdate

findByIdAndUpdate is also static method. It updates the object according provided filter and returns a Promise with object or null

let newMessageText = 'this is new message text'
// if we need updated object
const message = await Message.findByIdAndUpdate('some message id', {messageText: newMessageText})
// also we can ignore promise payload 
await Message.findByIdAndUpdate('some message id', {messageText: newMessageText})

findByIdAndDelete

findByIdAndDelete is static. It delete the object according provided id and returns a Promise without payload (void)

await Message.findByIdAndDelete('some message id')

---

Errors

With model creation we should provide all required parameters without default values. Also we have to pass values of the correct types.

If we make the mistake, we get one of following error messages:

Property "messageText" is required on type Message

Property "messageLikes" does not exist on type Message

Property "messageText" should be "string" type but got "number"