nekdis

Nekdis

What is it?

Nekdis is the temporary name for a proposal for redis-om that aims to improve the user experience and performance by providing an ODM-like naming scheme like the famous library mongoose for MongoDB

Future Plans

Right now the proposal includes almost every feature that redis-om already has (See: Missing Features) and introduces some like References.

The next steps for the proposal include:

• Improve performance on parsing nested objects for hashes¹
• Improving auto fetch performance by including a lua script that will get injected as a redis function.
• Allow auto references to be updated.
• Improve reference checking
• Adding support for objects inside arrays.
• Make a proposal for node-redis to improve its performance.

Table of contents

• Nekdis
  • What is it?
  • Future Plans
• Table of contents
• Installation
• Getting Started
  • Connecting to the database
  • Creating a Schema
  • Creating a Model
  • Creating and Saving data
• The new RecordId
• Vector Similarity Search
  • Pure queries
  • Hybrid queries
  • Range queries
• Custom Methods
• Modules
• Schema Types
• Field Properties
  • Shared Properties
  • Unique Properties
• Missing features
• Todo
• Nekdis VS Redis-OM
  • Client
  • Schema
  • Model vs Repository
    • Nekdis Document
      • Creating and saving
      • Creating and mutating
  • Search
  • Nested objects
  • A Simple example
  • Open Issues this proposal fixes
  • Benchmarks

Installation

Nekdis is available on npm via the command

npm i nekdis

Getting Started

Connecting to the database

Nekdis already exports a global client but you can also create your own instance with the Client class.

import { client } from "nekdis";

client.connect().then(() => {
    console.log("Connected to redis");
});

Creating an instance

import { Client } from "nekdis";

const client = new Client();

client.connect().then(() => {
    console.log("Connected to redis");
});

Creating a Schema

The client provides a helper to build a schema without any extra steps.

import { client } from "nekdis";

const catSchema = client.schema({
    name: { type: "string" }
});

Creating a Model

The client also provides a helper to create a model.

import { client } from "nekdis";

const catModel = client.model("Cat", catSchema);

Creating and Saving data

The model is what provides all the functions to manage your data on the database.

const aCat = catModel.createAndSave({
    name: "Nozomi"
});

The new RecordId

This proposal introduces a new way to create unique ids called RecordId.

RecordIds allow you to set prefixes and other properties to your id that is shared across all of the records.

Vector Similarity Search

There are 3 types of vss queries as said in the documentation

Lets use the following schema & model for the next examples

import { client } from "nekdis";

const testSchema = client.schema({
    age: "number",
    vec: "vector"
})

const testModel = client.model("Test", testSchema);

A note on the schema. Passing the string "vector" will default to the following options:

const vectorDefaults = {
    ALGORITHM: "FLAT",
    // the vector type, nekdis calls it `vecType`
    TYPE: "FLOAT32",
    DIM: 128,
    // nekdis calls it `distance`
    DISTANCE_METRIC: "L2",
}

Pure queries

testModel.search().where("vec").eq((vector) => vector
    .knn()
    .from([2, 5, 7])
    .return(8))
.returnAll();
// Generates the following query
// "*=>[KNN 8 @vec $BLOB]" PARAMS 2 BLOB \x02\x05\x07 DIALECT 2

Hybrid queries

testModel.search().where("age").between(18, 30)
    .and("vec").eq((vector) => vector
        .knn()
        .from([2, 5, 7])
        .return(8))
    .returnAll();
// Generates the following query
// "((@age:[18 30]))=>[KNN 8 @vec $BLOB]" PARAMS 2 BLOB \x02\x05\x07 DIALECT 2

Range queries

testModel.search().where("vec").eq((vector) => vector
    .range(5)
    .from([2, 5, 7]))
.returnAll();
// Generates the following query
// "((@vec:[VECTOR_RANGE 5 $BLOB]))" PARAMS 2 BLOB \x02\x05\x07 DIALECT 2

Custom Methods

In this proposal you can create your own custom methods that will be added to the Model, this methods are defined on the schema directly.

WARNING: Anonymous functions cannot be used when defining custom methods/functions

const albumSchema = client.schema({
    artist: { type: "string", required: true },
    name: { type: "text", required: true },
    year: "number"
}, {
    searchByName: async function (name: string) {
        return await this.search().where("name").matches(name).returnAll();
    }
})

const albumModel = client.model("Album", albumSchema);

const results = await albumModel.searchByName("DROP");

Modules

Nekdis allows you to add modules to the client, modules are something that adds extra functionality to the library, you pass in a class where the constructor will receive the client as its first argument.

Keep in mind that this might be more useful if you are creating your own instance of the client and exporting it because that way you will also get intellisense for the module.

import {type Client, client} from "nekdis";

class MyModule {
    constructor(client: Client) {
        // Do something
    }

    myFunction() {
        // Do something
    }
}

client.withModules({ name: "myMod", ctor: MyModule });

// Access it
client.myMod.myFunction()

Schema Types

This proposal adds some new data types and removes the string[] & number[] types.

Type	Description
string	A standard string that will be indexed as TAG
number	A standard float64 number that will be indexed as NUMERIC
bigint	A javascript BigInt that will be indexed as TAG
boolean	A standard boolean that will be indexed as TAG
text	A standard string that will be indexed as TEXT which allows for full text search
date	This field will internally be indexed as NUMERIC, it gets saved as a Unix Epoch but you will be able to interact with it normally as it will be a Date when you access it
point	This is an object containing a latitude and longitude and will be indexed as GEO
array	Internally it will be indexed as the type given to the elements property which defaults to string
object	This type allows you to nest forever using the properties property in the schema and what gets indexed are its properties, if none are given it will not be indexed not checked
reference	When using this type you will be given a ReferenceArray which is a normal array with a reference method that you can pass in another document or a record id to it, references can be auto fetched but auto fetched references cannot be changed
tuple	Tuples will be presented as per-index type safe arrays but they are dealt with in a different way. They will be indexed as static props so you can search on a specific element only, this also affects the query builder instead of where(arrayName) it will be where(arrayName.idx.prop) but this has working intellisense just like all the other fields so it shouldn't be an issue
vector	A vector field that is an array but indexed as VECTOR

Field Properties

This proposal includes the addition of 2 new shared properties and some unique ones

Shared Properties

Property	Description
type	The type of the field
optional	Defines whether the field is optional or not (this doesn't work if validation is disabled)
default	Chose a default value for the field making so that it will always exist even if it isn't required
index	Defines whether the field should be indexed or not (defaults to false)
sortable	Defines whether the field is sortable or not (note that this doesn't exist nor work on object fields & reference fields)

Unique Properties

Vector properties wont be documented here, check the types instead

Property	Type	Description
elements	array	Defines the type of the array
elements	tuple	Even tho it has the same name this field is required in tuples and there are no ways to define infinite length tuples (just use normal arrays)
separator	array	This defines the separator that will be used for arrays on hash fields
properties	object	The properties the object contains, if this isn't defined the object wont be type checked nor indexed
schema	reference	This is a required property when using references and it allows for intellisense to give the types on auto fetch and later on for certain type checking to also work as well
literal	string | number | bigint	Make it so that the saved value has to be exactly one of the literal values
caseSensitive	string	Defines whether the string is case sensitive or not
phonetic	text	Choose the phonetic matcher the field will use
weight	text	Declare the importance of the field

Missing features

• Custom alias for a field².

Todo

• in operator for number search
• Array of points
• Fully support array of objects
• Add $id alias³

Nekdis VS Redis-OM

In this part of the document im going to cover how this proposal compares to the current redis-om (0.4.2) and the major differences.

Client

In Nekdis the Client does not provide any methods to interact directly with the database and its pretty much only used to store your models and handle the connection, however you can access the node-redis client by accessing client.raw.

Schema

The schema in Nekdis is just where you define the shape of your data while in redis-om it also takes care of creating indexes and some other internal bits.

With this comes the big question "Well, why not use just a plain object then", the simple answer to this question is ease of use but to explain it further, having the schema defined this way allows the library to internally check if there isn't anything missing and parse it so you are allowed to use the shorthand methods like field: "string", this approach also allows for you to define methods an options that will be passed down to the model down the road and not to mention that this is one of the only ways to have references working properly without affecting performance.

Model vs Repository

In redis-om you use a repository to interact with the db by using methods like fetch, save and search.

In Nekdis the model is not that different but it allows you to add more functionality to it (see: Custom Methods) and overall gives more functionality out of the box.

Nekdis Document

In Nekdis you have what are called documents, this is just an abstraction to the data to allow better interaction with references and faster parsing.

At first this might look daunting compared to redis-om that now uses plain objects but i can assure you that there isn't that much of a difference, and i will give some examples to demonstrate it.

Creating and saving

See, its just as easy

Nekdis	Redis-OM
await model.createAndSave({ name: "DidaS" });	await repository.save({ name: "DidaS" });

Creating and mutating

This is where things start to be a bit different, even tho you can use a plain object that isn't recommended since it would just use more memory.

Nekdis	Nekdis with plain object	Redis-OM
// You can pass values directly to it // just like in createAndSave const data = model.create({ name: "DidaS" }); // mutate data data.year = 2023; await model.save(data);	// Doing it this way will use more memory // and you wont have intellisense const data = { name: "DidaS" } // mutate data data.year = 2023; await model.createAndSave(data);	const data = { name: "DidaS" } // mutate data data.year = 2023; await repository.save(data);

Search

Looking at search for the first time it is pretty much the same, the only difference is that equals operations exist in every data type so a lot of times changing the data type in the schema wont break the query and the best part is that eq, equals and other operators like them support arrays (so they pretty much work like an in operator).

Nested objects

Currently in redis-om you need to define a path for each field to define your nested objects, meanwhile in Nekdis they just work like normal js objects!

There are several advantages to this, two of the main ones being, faster serialization/deserialization and simpler to use, here is an example comparing both

Nekdis	Redis-OM
client.schema({ field: { type: "object", properties: { aNumberInsideOfIt: "number", nesting: { type: "object", properties: { doubleNested: "boolean" } } } } })	Schema("OM", { aNumberInsideOfIt: { type: "number", path: "$.field.aNumberInsideOfIt" }, doubleNested: { type: "boolean", path: "$.field.nesting.doubleNested" } })

A Simple example

This is a simple program example that generates 30 random users with random ages and fetches the ones matching a certain age just to show the differences between the libraries

Nekdis

Redis-OM

// Import the global client import { client } from "nekdis"; // Connect to the db await client.connect(); // Create the schema const userSchema = client.schema({ age: "number" }, { // Define function to help repetitive task findBetweenAge: async function (min: number, max: number) { return await this.search().where("age").between(min, max).returnAll(); } // Add creation date to the key }, { suffix: () => Date.now().toString() }); // Create the interface const userModel = client.model("User", userSchema); // Create the search index await userModel.createIndex(); // Generate 30 users for (let i = 0; i < 30; i++) { await userModel.createAndSave({ age: between(18, 90) }); } // Get the users that are between 30 and 50 years old const users = await userModel.findBetweenAge(30, 50); // Log the users console.log(users) // Close the connection await client.disconnect(); // A helper function that generates a random number between min and max function between(min: number, max: number) { return Math.round(Math.random() * (max - min + 1)) + min; };

// Node stuff for the id import { randomUUID } from "node:crypto"; // Import the redis client import { createClient } from "redis"; // Import OM utilities import { Schema, Repository, Entity, EntityId } from "redis-om"; // Create Client const client = createClient() // Connect to the db await client.connect(); // Create the schema const userSchema = new Schema("User", { age: { type: "number" } }); // Create an interface to allow type safe manipulation // However you will need to use it everywhere // If you are using js you would need to do it in jsdoc for it to work interface UserEntity extends Entity { age: number } // Create the interface const userRepository = new Repository(userSchema, client); // Create the search index await userRepository.createIndex(); // Generate 30 users for (let i = 0; i < 30; i++) { await userRepository.save({ // We set the "suffix" and random id to somewhat match Nekdis (still not 100% accurate you would need even more) [EntityId]: `${Date.now()}:${randomUUID()}`, age: between(18, 90) }); } // Get the users that are between 30 and 50 years old const users = await findBetweenAge(userRepository, 30, 50); // Log the users console.log(users) // Close the connection await client.disconnect(); // Define function to help repetitive task async function findBetweenAge(repository: Repository, min: number, max: number): Promise<Array<UserEntity>> { // Type assertion so ts does not complain return <Array<UserEntity>>await repository.search().where("age").between(min, max).returnAll(); } // A helper function that generates a random number between min and max function between(min: number, max: number) { return Math.round(Math.random() * (max - min + 1)) + min; };

Open Issues this proposal fixes

• #25 (Use reflection to do object mapping for a more declarative API)
  • Achieves this purely on the type level working for both js and ts without extra steps and without the declarative (decorators) part
• #28 (Transactions & relations)
  • Relations are added and transactions are in the plans with a nice api like the c# lib
• #44 (Add in (eq for multiple values))
  • As mentioned in Search methods like equals work just like it
• #54 (Add boolean[] as a new type)
• #55 (Add number[] as a new type)
• #66 (Implement implicit transaction and locking in the context of redis-om for master-detail relations )
  • Partially done with relations
• #69 (Add default value to Schema)
  • Also required was added
• #85 (Vector Similarity Search)
• #120 (Add expireAt)
  • normal expire accepts both seconds or a date object
• #141 (Feature: "in" query clause functionality)
  • Same as issue #44
• #184 (Set a Global Prefix in Node Om)

Benchmarks

There were a lot of benchmarks made and they can be found here

Footnotes

• Currently the deepMerge function will take longer the more objects and nested objects you have, the idea i received is to do it all in one go by using a function to flatten it but im not sure yet on how to do it ↩

• Is this really needed? From my point of view the complexity required to add this would outweigh any benefits from it specially on the type-level transformations ↩

• This could be a nice addition but im still unsure if this should be added and needs to be further discussed ↩