Overview

This module manages a tiny and simple database, which is storing datasets as JSON files.

Naming and structure

The data is organized as one JSON file per data set in folders. The folders are referred to below as a database. The JSON files are referred to as documents.

All methods return promises.

All parameters are transferred in an object, that is being destructured in the method (a.k.a. Named Arguments).

Usage

Install the module to your project.

npm i chfiledb

The module can be imported to your nodeJS project as ES6 module.

import chFileDB from 'chfiledb';

Caching

Documents that are loaded, created or saved are stored in a cache. Subsequent read accesses then access the object in RAM instead of the file, which speeds up reading considerably.

Database Methods

The so-called database methods allow the manipulation of entire databases. This allows databases to be created, deleted and connected.

init()

By default the database is being stored in a subfolder of the module.

Parameter

• DBPath Absolute operating system path, where your databases will be stored.

Returning object contains:

• status The status of the operation

import chfiledb from 'chfiledb';
chfiledb.init({ DBPath: 'C:/Users/alfa/Desktop/data' }).then(
    console.log
).catch(
    console.warn
)

create()

Creates a new database with the given dbName as ID.

Parameters

• dbName: Defines the name of the new database. The name is case sensitive. This parameter is required, so no default provided.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning Object contains

• status: The status of the operation
• connection: Object to work with the created database immediately.

chfiledb.create({ name: 'mydb'}).then(
    console.log
).catch(
    console.warn
)

delete()

Deletes a database with the give dbName as ID.

Parameters

• dbName: Defines the name of the database to be deleted. The name is case sensitive. This parameter is required, so no default provided.
• debug: Gives additional outputs in case of an error. Defaults to false

Returning object contains:

• status: The status of the operation

chFileDB.delete({ dbName: 'myDB' }).then(
    console.log
).catch(
    console.warn
)

connect()

The connect() method creates a connection to the database. Actually, it checks, if the database is there and returns an object to interact with the database. See below.

Parameters

• name: Defines the name of the database to be connected to. This parameter is required, so no default provided.
• autoCreate: Controls whether the database should be created automatically if it does not exist. Defaults to true.
• debug: Gives additional outputs in case of an error. Defaults to false

Returning Object contains

• connection: Object to work with the created database immediately.

chFileDB.connect({
    dbName: 'myDB',
    autoCreate: true,
    debug: true,
}).then(
    console.log
).catch(
    console.warn
)

Document Methods

The document methods are contained in the return of the connect() method.

listIDs()

This method creates an array of all existing documents in the connected database. This is handy to get a full overview of the documents or to implement pagination.

This method does not use any parameter.

Returning object contains:

• status: The status of the operation
• payload: Array with the IDs

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.listIDs()
).then(
    console.log
).catch(
    console.warn
)

createDoc()

This method creates a new document in the connected database. The method can get the following parameters.

Parameters:

• payload: Contains an object to be stored in the document. If the object doesn't contain an attribut id, it will be created automatically.
• overwrite: If set to true, a document with the same id will be overwritten. There will be no confirmation and no backup. Defaults to false.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains:

• status: The status of the operation
• connection object: To chain more methods
• payload: The Object, that has been written to the database

const rezept = {
    name: "Pasta Carbonara",
    zubereitungszeit: 30,
    portionen: 4
};
const film = {
    titel: "Inception",
    regisseur: "Christopher Nolan",
    jahr: 2010,
};

chFileDB.connect({
    dbName: 'myDB'
}).then(
    conn => conn.createDoc({
        payload: rezept
    })
).then(
    conn => conn.createDoc({
        payload: film
    })
).catch(
    console.warn
)

loadDoc()

This method is loading a single document with a given ID.

Parameters

• id: ID of the document to be loaded. This parameter is required, so no default provided.
• ignoreCache: The cache is ignored and the data record is read from the file.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation
• doc: Document as stored currently
• connection: Connection to the database to chain more operations
• cached: Info, if the loaded data has been read from cache

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.loadDoc({ id: '2486ikkhe1q' })
).then(
    console.log
).catch(
    console.warn
)

loadDocs()

This method is loading a bunch of documents based on a given array of IDs.

Parameters

• ids: Expects an array of IDs of the documents to be loaded.
• ignoreCache: The cache is ignored and the data record is read from the file.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation
• docs: Array with the documents referred to by the IDs. An ID, that doesn't lead to a document, returns undefined.
• connection: Connection to the database to chain more operations

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.loadDocs({
        ids: [
            '14hrd1th3px',
            '2486ikkhe1q',
            'pinuc3ldigw'
        ]
    })
).then(
    console.log
).catch(
    console.warn
)

updateDoc()

This method updates and adds attributes into a document. The attributes of the document remain unaffected unless they are given a new value.

Parameters

• payload: The attributes to be updated or added. The payload has to contain the ID of the document to be updated.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation
• doc: Document as stored currently
• connection: Connection to the database to chain more operations

// Document before updating
// {
//  id: "2486ikkhe1q",
//  customNum: 13
// }

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.updateDoc({
        payload:{
            id:'2486ikkhe1q',
            anAttr: 1000
        }
    })
).then(
    console.log
).catch(
    console.warn
)

// {
//  id: "2486ikkhe1q",
//  customNum: 13,
//  anAttr: 1000
// }

deleteDoc()

This method deletes a single document. There is no security check or backup so be sure, that you indeed want to delete the document.

Parameters

• id: The id of the document to delete. This parameter is required, so no default provided.
• payload: Instead of an ID, you can transfer the object to be deleted. The method then takes the id from that object.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation

chFileDB.connect({
    dbName: 'myDB'
}).then(
    conn => conn.deleteDoc({
        id: 'q6igqag1sxs'
    })
)

hideDoc()

This method hides a document as an alternative to delete it. Hidden documents are intended to be treated just like deleted documents. But with the possibility to regain the data.

Parameters

• id: ID of the document to be hidden
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation
• doc: Document as stored currently
• connection: Connection to the database to chain more operations

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.hideDoc({
        id: 'l5gg71jl90g',
    })
).then(
    console.log
).catch(
    console.warn
)

unhideDoc()

This method unhides a document, that has been hidden beforehand.

Parameters

• id: ID of the document to be unhidden
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation
• doc: Document as stored currently
• connection: Connection to the database to chain more operations

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.unhideDoc({
        id: 'l5gg71jl90g',
    })
).then(
    console.log
).catch(
    console.warn
)

findDoc()

This method will search for documents that fit a given pattern.

To be done

deleteAttribute()

This method deletes given attributes from a document.

Parameters

• id: Document ID, in which the attribute shall be removed.
• attributes: An array with te attribute key to be remove.
• debug: Gives additional outputs in case of an error. Defaults to false.

Returning object contains

• status: Status of the operation
• doc: Document as stored currently
• connection: Connection to the database to chain more operations

// Document before updating
// {
//  id: "2486ikkhe1q",
//  customNum: 13,
//  a1: 100
// }

chFileDB.connect({ dbName: 'myDB' }).then(
    conn => conn.deleteAttributes({
        id: '2486ikkhe1q',
        attributes: [
            'a1'
        ],
        debug: true
    })
).then(
    console.log
).catch(
    console.warn
)


// Document after updating
// {
//  id: "2486ikkhe1q",
//  customNum: 13
// }