Express + TypeScript + Sequelize Starter Template (with Migrations)

This repository contains a starter template using Express, TypeScript and Sequelize ORM based on this repository. It also supports migrations, albeit in a bit of a hacky way.

Naming convention for environment variables files

Apart from the .env.example file, the src/config/index.ts file expects one of the following three files (based on the value of NODE_ENV):

• .env.development.local
• .env.production.local
• .env.test.local

Essentially, it follows .env.${NODE_ENV}.local format for the filenames.

How to achieve migrations and seeding

Due to how sequelize is wired to work best with JavaScript and not TypeScript, some workarounds needs to be used for usage of migrations and seeding.

• .sequelizerc file at the project root points to the dist folder (i.e. after TypeScript code has been transpiled to JavaScript).
• So, the migration and seed commands will place the ${timestamp}_${migration_name}.js and ${timestamp}_${seeder_name}.js files in the dist/migrations and dist/seeders folders, respectively.
• You need to copy the .js files to the src/migrations or src/seeders folders.
• You need to change the extension from .js to .ts.
• You need to change the structure to a TS based migration or seed file. A template structure is given below:

"use strict";
import { Sequelize as TSequelize, QueryInterface } from "sequelize";

module.exports = {
  async up(queryInterface: QueryInterface, Sequelize: TSequelize) {
    const transaction = await queryInterface.sequelize.transaction();

    try {
      /**
       * Add altering commands here.
       *
       * Example:
       * await queryInterface.createTable('users', { id: Sequelize.INTEGER });
       */
      await transaction.commit();
    } catch (err) {
      console.error(err);
      await transaction.rollback();
    }
  },

  async down(queryInterface: QueryInterface, Sequelize: TSequelize) {
    const transaction = await queryInterface.sequelize.transaction();

    try {
      /**
       * Add reverting commands here.
       *
       * Example:
       * await queryInterface.dropTable('users');
       */
      await transaction.commit();
    } catch (err) {
      console.error(err);
      await transaction.rollback();
    }
  },
};

• Now, when you finish writing your migrations and seed files and build the project, the dist folder will contain the JS version of the same, and hence .sequelizerc will be able to apply your migrations.

For convenience, the commands to generate migration or seed files are given below:

Creating migrations

npx sequelize-cli migration:generate --name "migration_name"

Creating seeders

npx sequelize-cli seed:create --name "seed_name"

Formatting code

Before committing your code, You can run yarn format to properly format all files in the repository based on the settings defined in the .prettierrc file at the root of the repository.