@tusent.io/json-database

json-database

A Node.js module for storing data in files on the local machine. It's basically a settings manager.

This is only meant to be used by a single application since it doesn't automatically reload the file after another application has edited it. When it saves the file, it rewrites the entire file to disk.

Install

json-database is available for installation through npm using the npm install command.

npm install @tusent.io/json-database --save

Usage

const Database = require('json-database');

// Load existing database or create
const db = new Database('./data.json');

// Gets with specified defaults
let dataVersion = db.get('dataVersion', Number.MIN_SAFE_INTEGER);
let userCount = db.get('userCount', 0);

/**
 * If performance is not of the essence:
 */
if (dataVersion < 7) {
    // Save backup file to './data.json.bak'
    db.save(db.path + '.bak');
    
    for (let i = 0; i < userCount; i++) {
        let username = db.get(`users.${i}.name`); // (defaults to null)
        if (username !== null) {
            // Save for each setting
            db.set(`users.${i}.name`, null);
            db.set(`username${i}`, username);
        }
    }
    
    db.set('dataVersion', 7);
    console.log('Updated database to data version 7.');
}

/**
 * Same thing but more performant (fewer writes to disk):
 */
if (dataVersion < 7) {
    // Save backup file to './data.json.bak'
    db.save(db.path + '.bak');
    
    for (let i = 0; i < userCount; i++) {
        let username = db.get(`users.${i}.name`); // (defaults to null)
        if (username !== null) {
            // Set values without saving
            db.set(`users.${i}.name`, null, false);
            db.set(`username${i}`, username, false);
        }
    }
    
    // Save database file
    db.save();
    
    // Saves here as well (above save is redundant)
    db.set('dataVersion', 7);
    console.log('Updated database to data version 7.');
}

Note that I/O errors thrown by the fs-module are not caught and must be caught by the user of this module. The affected methods are Database.save, Database.set (unless called with save parameter set to false), and Database.constructor.

License

LGPL-3.0