brandonbloom/jseg

---

brandonbloom/jseg.json

{
  "createdAt": "2015-11-25T17:03:40Z",
  "defaultBranch": "master",
  "description": "A super simple, in-memory, JS graph database.",
  "fullName": "brandonbloom/jseg",
  "homepage": "",
  "language": "JavaScript",
  "name": "jseg",
  "pushedAt": "2022-02-25T21:55:42Z",
  "stargazersCount": 482,
  "topics": [
    "datomic",
    "graph-database",
    "graphql",
    "json",
    "relay"
  ],
  "updatedAt": "2025-10-12T00:54:42Z",
  "url": "https://github.com/brandonbloom/jseg"
}

JavaScript Entity Graph

An in-memory graph database for JavaScript data.

Overview

• Entity/Attribute/Value graph-based information model.
  • Schema enforces relationships, provides unique indexes, and validates data.
• Operates on plain-old JavaScript objects.
  • Hierarchical data is flattened on put and reconstituted on get.
  • Not necessarily just JSON (allows dates, etc).
• No spooky action at a distance.
  • Every graph operation makes an implicit defensive copy.
  • Many of the benefits of immutability without loss of JavaScript idioms.

Status

This is version 2 with lots of new/improved stuff and is deployed in at least one real product. I’m not personally working on that product anymore, but this version has been pretty stable and useful there, so I don’t expect much if any churn. I’m unlikely to consider major feature requests, but bug fixes are still welcome.

See [the v1 readme][2] for rationale, background, goals, etc.

Usage

This is just a taste. See [docs]!(./doc) for more details.

let jseg = require('jseg');

let [builder, types] = jseg.newSchema();

builder.entity('User');
builder.trait('Likeable');
builder.entity('Comment', types.Likeable);
builder.entity('Link', types.Likeable);

builder.finalize({

  attributes: {

    User: {
      name: types.Text,
    },

    Comment: {
      createdAt: types.Time,
      message: types.Text,
    },

    Link: {
      href: types.Key,
    },

  },

  relationships: [

    [[types.Likeable, 'many', 'likers'],
     [types.User, 'many', 'likes']],

    [[types.Comment, 'one', 'author'],
     [types.User, 'many', 'comments', {
       compare: (a, b) => Math.sign(a.createdAt - b.createdAt)
     }]],

  ],

});


let graph = new jseg.Graph(types);

graph.put({

  type: 'User',
  lid: 'user:brandonbloom',
  name: 'Brandon Bloom',

  comments: [
    {
      type: 'Comment',
      lid: 'comment-1',
      createdAt: new Date('Sat May 21 2016 12:59:48 GMT-0700 (PDT)'),
      message: 'It is kind of weird to like your own comments.',
    },
    {
      type: 'Comment',
      lid: 'comment-2',
      createdAt: new Date('Sat May 21 2016 12:59:51 GMT-0700 (PDT)'),
      message: 'This is a very important comment.',
    },
  ],

  likes: [
    {
      type: 'Link',
      lid: 'link-1',
      href: 'example.com',
    },
    {
      type: 'Comment',
      lid: 'comment-1',
    }
  ],

});

console.log(graph.get('user:brandonbloom'));

console.log(graph.get('comment-1', {depth: 3, json: true}));

console.log(graph.lookup('Link', 'href', 'example.com'));

graph.destroy('comment-2');
console.log(graph.get('comment-2'));

[1] !: https://github.com/brandonbloom/jseg/tree/v1 [2] !: https://github.com/brandonbloom/jseg/blob/v1/README.md