generic-repo

    2.1.0 • Public • Published

    generic-repo

    Generic Repository for objects, based on knex.

    Build Status

    Install

    $ npm i --save generic-repo

    Usage

    A persistable Class

    A Class can be persisted if it satisfies the following criteria:

    • 1st argument of it's constructor accepts an Object that contains at least all the persistable properties.
    • It has a props property that contains all the props that should be persisted.

    Property serialisation

    Complex property values

    If a prop is of type Object it will be converted into a JSON before inserting into the database. You should handle this case appropriately in your Class constructor (see children prop of User below).

    Non-complex prop values

    Non-complex values such as Number, String, Boolean are send to the database as-is.

    class User {
      constructor(data) {
        this.props = {  
          id_user: data.id_user,
          name: data.name,
          // Some DB's might not support a JSON datatype.
          // Therefore we might also need to *parse* back the result.
          children: data.children
            ? typeof data.children === 'string'
              ? JSON.parse(data.children)
              : data.children
            : []
        }
    
        // Anything outside `props` will *not* be persisted
        // - e.g `age` property will not be persisted
        this.age = 15
      }
    
      getName() {
        return this.name
      }
    }

    A usage example using the above User Class:

    const GenericRepo = require('generic-repo')
    const knex = require('knex')({
      client: 'sqlite3',
      connection: { filename: './test_db.sqlite' }
    })
    
    const genericRepo = new GenericRepo({
      tableName: 'user',
      primaryKey: 'id_user',
      constructAs: data => new User(data)
    })
    
    genericRepo.upsert(knex, new User({
        id_user: 'lxkkfv',
        name: 'John Doe'
      }))
      .then(() => {
        return genericRepo.get(knex, { id_user: 'lxkkfv' })
      })
      .then(user => {
        console.log(user.getName()) // 'John Doe'
      })

    Ensure that your DB already has the table/columns you declared when you instantiated the repo.

    API

    upsert(knex, instance)

    • Inserts the instance if it does not exist by primary key.
    • Updates the instance if it already exists by primary key.
    genericRepo.upsert(knex, user).then(() => {
      console.log(result) // [1]
    })

    getAll(knex, filter)

    • If no filter is provided it returns all saved instances.
    • If a filter is provided it returns just the matched instances.
    genericRepo.getAll(knex, { name: 'John Doe' }).then(users => {
      console.log(users[0].getName()) // logs 'John Doe'
    })

    get(knex, filter)

    • Returns an instance that matches the filter.
    • Returns undefined if no instance is found.
    genericRepo.getAll(knex, { name: 'John Doe' }).then(user => {
      console.log(result) // logs the 'John Doe' instance
    })

    exists(knex, filter)

    • Returns true if a result is found, false otherwise.
    genericRepo.exists(knex, { name: 'John Doe' }).then(result => {
      console.log(result) // logs `true`
    })

    del(knex, filter)

    • Removes/Deletes the instance that matches the filter.
    • Does nothing if no instance is found (no-op).
    genericRepo.del(knex, { name: 'John Doe' }).then(() => {
      // Instance with name 'John Doe' was removed from the DB
    })

    Extend this repository

    This module exports an ES6 Class which you can simply extend.

    const GenericRepo = require('generic-repo')
    
    class MySuperWowRepo extends GenericRepo {
      constructor() {
        super({
          tableName: 'employees',
          primaryKey: 'id_employee',
          constructAs: data => new Employee(data)
        })
      }
    
      getAllJohnDoes(knex) {
        return knex(this.tableName)
          .where({ name: 'John Doe' })
      }
    }

    Test

    $ npm test
    

    Authors

    License

    MIT

    Install

    npm i generic-repo

    DownloadsWeekly Downloads

    4

    Version

    2.1.0

    License

    MIT

    Unpacked Size

    14.2 kB

    Total Files

    10

    Last publish

    Collaborators

    • nicholaswmin