Watch your filesystem-directories-and-JSON based storage, keep all data in RAM and HDD.

$ npm install --save jsondir-livedb

const LiveDB = require('jsondir-livedb');
var DB = new LiveDB(settings);

Settings is the object containing these keys:

• root (required) - storage directory
• instantPush sets whether any change will be applied to storage instantly
• liveIgnore sets whether changes in filesystem will be ignored (default: false)
• pathSep sets separator for relative paths in tree (default: '/')
• unwatch sets whether watcher is not supposed to be used
• watch represents options for watcher (https://www.npmjs.com/package/watch#watchwatchtreeroot-options-callback)

Root folder must be in your working directory already. In example it is called storage.

Now you can put some files into this folder. Be it any folders with markdown and other meta files, library will touch JSON files only.

const LiveDB = require('jsondir-livedb');
var DB = new LiveDB({
    root: 'storage'
});

if (DB.set('unnecessary/file.json')) {
    console.log('Succesfully created');

    console.log(DB.get('unnecessary/file.json')); // returns {}

    console.log(DB.tree['unnecessary']['file.json']); // returns {}
    console.log(DB.tree.unnecessary['file.json']); // returns {}

    console.log(DB.tree.unnecessary.file); // returns undefined

    if (DB.delete('unnecessary/file.json')) {
        console.log('Succesfully deleted');
    }
}

DB.set('users/1/common.json', null, {
    name: 'admin',
    password: 'admin',
    class: 5
});

console.log(require('util').inspect(DB.tree, {colors: true, depth: 5}));

DB.set('users/1/common.json', 'authKey', 'big secret');

DB.delete('users/1/common.json', 'class');

All previous changes were made in runtime only. So make them in the storage too:

DB.push();

Put a setting instantPush: true if you want to apply changes (set, delete) to storage instantly without calling function above.

...
var DB = new LiveDB({
    root: 'storage',
    instantPush: true
});
...

By default your database has ability to watch and fetch changes in storage in runtime.

Set interval to output JSON file contents:

setInterval(() => {
    var contents = DB.tree.users['1']['common.json'];
    console.log('\n'+ require('util').inspect(contents, {colors: true, depth: 5}));
}, 5000);

Now make some changes in file users/1/common.json via any other program. See the difference.

So delete JSON files in users now and push the changes:

DB.delete('users');
DB.push();// if you prefer not to use `instantPush`

Note that folders were not deleted. You can remove empty directories in your storage with tools like ded, remove-empty-directories, etc.