No data? No problem!

Automatically seed your database with production-like dummy data based on your schema for local development and testing.

Automated values

Seed automatically determines the values in your database so you don’t have to define each and every value unless you want to be specific, in which case you just use Typescript to define those values. Our default data automatically adds necessary built-ins, like country lists, currency codes etc.

Automated relationships

Seed automatically creates relational entities so you don’t have to keep track of IDs in one table when you’re defining values in another.

Type-safe by default

await seed.posts([{
  title: "Why you need Seed",
  author: {
    email: "snappy@snaplet.dev",
  },
  comments: (x) => x(3),
}]);

Seed creates a TypeScript client based off your database structure. Values are safe, and soft documented. You have the full power of the typescript language and the rich node.js infrastructure when seeding production-like data and defining data values.

Deterministic data

Seed uses Copycat for its data generation functions, and all data generation is fully deterministic. That means if you use the same inputs, you'll always get the same data outputs. That makes seed great for consistent tests and development.

Try out Seed

npx @snaplet/seed init

Learn more by reading our documentation.

AI-Generated Data

Use a Large Language Model (LLM) to generate examples for text-based entries. To use this feature, set up one of the following environment variables in your .env file:

OPENAI_API_KEY=<your_openai_api_key>
GROQ_API_KEY=<your_groq_api_key>

Optionally, specify the AI model name with the AI_MODEL_NAME environment variable. Example: AI_MODEL_NAME=gpt-4-mini

The predicted data is saved in the file .snaplet/dataExamples.json and can be modified by the user.

Here is an example of a dataExamples.json file:

[
  {
    "input": "post title",
    "examples": [
      "Tips for Effective Time Management",
      ...
    ],
    "description": "This column is about storing the titles of the user-generated posts in the project."
  },
  ...
]

In the above example, one could modify the description and remove the examples. Running npx @snaplet/seed sync will then regenerate examples based on the updated description for that column.

Documentation

You can find the hosted documentation here.

The docs are also in this repo in the docs folder. To host it locally follow below instructions:

Prerequisites

Install brew, git, pnpm and Node.js :

Installation

cd docs
pnpm install

Run the project

pnpm dev
# Go to http://localhost:3000

Contributions

Setup local development environment

1. Install and configure Nix

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install \
  --extra-conf "substituters = https://cache.nixos.org https://devenv.cachix.org" \
  --extra-conf "trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= devenv.cachix.org-1:w1cLUi8dv3hnoSPGAuibQv+f9TZLr6cv/Hm9XgU50cw="

We now need to install direnv (or its nix-optimized variant nix-direnv) in order to automatically load our system dependencies when navigating to our project's folder.

2.1. Install direnv with Home Manager (optional but recommended)

Home Manager allows you to configure your user's shell environment with Nix.

nix run home-manager/master -- init

Edit ~/.config/home-manager/home.nix with your preferences. Here is mine:

{ pkgs, ... }:

{
  home.username = "jgoux";
  home.homeDirectory = "/Users/jgoux";

  home.stateVersion = "23.05";

  home.packages = [
    pkgs.cachix
    pkgs.corepack_20
    pkgs.nodejs_20
    pkgs.nil
    pkgs.nixpkgs-fmt
  ];

  home.sessionVariables = {
    EDITOR = "code-insiders";
    DIRENV_LOG_FORMAT = "";
  };

  programs = {
    home-manager.enable = true;

    # direnv is installed here!
    direnv = {
      enable = true;
      enableZshIntegration = true;
      nix-direnv.enable = true;
    };

    zsh = {
      enable = true;
      autosuggestion.enable = true;
      syntaxHighlighting.enable = true;
      oh-my-zsh = {
        enable = true;
        plugins = [ "git" ];
        theme = "robbyrussell";
      };
      initExtra = ''
        export PATH="$PATH:/usr/local/bin:/opt/homebrew/bin"
      '';
    };
  };
}

Apply your home.nix configuration:

nix run home-manager/master -- init --switch

From now on when you will need to re-apply your configuration after editing home.nix you will just have to run:

home-manager switch

2.2. Install direnv with nix profile

If you don't want to manage your home dependencies with home-manager and you just want to install direnv you can do:

nix profile install nixpkgs#nix-direnv

Then add nix-direnv to $HOME/.config/direnv/direnvrc:

source $HOME/.nix-profile/share/nix-direnv/direnvrc

3. Open snaplet/seed repository in your editor

Now that you have direnv installed, it should automatically load the necessary system dependencies when you launch a new terminal in the snaplet/seed project.

You can then start your local PostgreSQL server (running on port 2345) by doing: devenv up.

License

MIT License