Datastore

A datastore module by Matt Balmer.

Can be used fine with either plain JavaScript, or with TypeScript for additional benefits.

The documentation below will be marked with TypeScript.

Installation

npm i --save mbalmer-datastore

Import with:

import { Datastore } from 'mbalmer-datastore'; or const { Datastore } = require('mbalmer-datastore');

Usage

Instantiating New Datastore

To create a new datastore:

const datastore = new Datastore();

The default data will be an empty object {}. If you have data to default to, or an interface, the following will work:

const datastore = new Datastore<YourInterface>({
  your: 'defaultObject',
  foo: {
    bar: 'hello',
  },
});

Functions

exists(path)

Returns a boolean if the given path exists.

get(path, [default])

Returns the value at a given path, or default if it does not exist.

set(path, value)

Sets the value at a given path.

update(path, value, [force])

Updates the value at a given path, as long as it exists. Throws an error if it does not.

If the force flag is true, it will call set() with the given parameters.

insert(path, value, [pos])

Inserts a value into an array field. If the path specified is not an array, an error will be thrown.

A callback for an insert operation will also contain the delta (the value given in the insert() call), and the position inserted at.

subscribe(callback)

There are several ways to call subscribe:

datastore.subscribe(callback) datastore.subscribe(path, callback) datastore.subscribe(path, operation, callback)

Where path and operation are optional arguments that server to filter which operations call the given callback.

For example, if called with datastore.subscribe('users', 'insert', callback), operations setting other paths, or setting the same path but with a different operation, would not trigger the callback.