Running the App

Four CLI commands cover the full local lifecycle: write code with dev, compile with build, run the compiled output with prod, and (optionally) do the whole thing inside Docker with container-dev.

Command	What it does
dev	Hot-reload dev server via tsx --watch
build	tsc -p tsconfig.build.json; rewrites alias imports in opinionated projects
prod	node against the compiled JavaScript
container-dev	Docker-compose-based development workflow (start, stop, attach, shell, status, logs)

All four read expressots.config.ts from the project root and the compile path from tsconfig.build.json.

Prerequisites

File	Purpose
expressots.config.ts	Provides entryPoint and opinionated flags.
tsconfig.build.json	Must define compilerOptions.outDir. Used by build (output) and prod (input).

dev

Hot-reload local dev server.

expressots dev

Under the hood it shells out to:

npx tsx --watch [-r tsconfig-paths/register] ./src/<entryPoint>.ts

• tsx --watch is tsx's built-in watch mode with no nodemon, no SIGTERM quirks on Windows.
• tsconfig-paths/register is added for opinionated projects so @useCases/..., @providers/... etc. resolve at dev time.
• The process inherits stdio; press Ctrl+C to stop. Saved files trigger a fast restart.

Options

Flag	Alias	Default	Description
--container	-c	false	Run dev inside Docker. Generates Dockerfiles + compose if missing.
--build	-b	false	(With --container) Rebuild the dev container before starting.
--detach	-d	false	(With --container) Run the dev container in the background.

expressots dev --container --build --detach

When --container is set, the CLI invokes Compose v2 (docker compose) when available and falls back to Compose v1 (docker-compose). Both Dockerfile.development and docker-compose.development.yml are generated on demand.

build

Compile to JavaScript.

expressots build

Under the hood:

npx tsc -p tsconfig.build.json

Then, for opinionated projects only, the CLI post-processes every emitted .js file:

• Replaces require("@alias/<path>") imports with relative paths so the compiled bundle runs without tsconfig-paths/register.
• Copies package.json into outDir so production tooling (npm prune --production, npm start, etc.) can resolve dependencies.

Why the rewrite

v3 required register-path.js at runtime. v4 removed that. Alias resolution is baked into build time, so production startup has zero path-mapping cost.

prod

Run the compiled output with plain Node.

expressots prod

The exact invocation depends on whether the project is opinionated:

opinionated	Command
true	node ./${outDir}/src/${entryPoint}.js
false	node ./${outDir}/${entryPoint}.js

In either case the alias rewrite has already happened during build, so production startup is just node <file>.

container-dev

Compose-driven development workflow. Use this when your dev story requires sidecar services (Postgres, Redis, RabbitMQ) and you want them all running on docker compose up.

Action	Purpose
start	(default) Boot the dev compose file in the foreground.
stop	Stop the dev compose stack.
attach	Attach to the app container's stdout.
shell	Open an interactive shell inside the app container.
status	Show running container state for the compose project.
logs	Tail the app container's logs.

expressots container-dev start --build
expressots container-dev logs --follow --tail 200
expressots container-dev shell
expressots container-dev stop

Options

Flag	Alias	Default	Description
--container	-c	false	Force the container path. Without this, start only prints guidance.
--service	-s	app	Service name from the compose file.
--compose-file	-f	docker-compose.development.yml	Compose file to use.
--build	-b	false	Rebuild images on start.
--detach	-d	false	Run start in the background.
--port	-p	(compose-driven)	Override the host port for start.
--debug-port		9229	Expose the Node inspector on this port.
--watch	-w	true	Mount source for live edits.
--follow		false	logs follow mode.
--tail		100	logs tail line count.

dev or container-dev?

• expressots dev is faster. tsx --watch reload is sub-second and there is no Docker layer.
• expressots dev --container is a one-shot containerized dev.
• expressots container-dev is the structured Compose workflow when you need multiple services and a long-lived dev environment.

Common scripts

expressots new emits these scripts in package.json:

{
  "scripts": {
    "dev":   "expressots dev",
    "build": "expressots build",
    "prod":  "expressots prod"
  }
}

So you can call them through your package manager too:

npm

npm run dev
npm run build
npm run prod

yarn

yarn dev
yarn build
yarn prod

pnpm

pnpm dev
pnpm build
pnpm prod

Troubleshooting

Problem	Fix
tsconfig.build.json: outDir missing	Add "outDir": "build" (or any folder name) under compilerOptions.
Cannot find module '@useCases/...' in production	You ran node directly. Use expressots prod so the alias rewrite is applied, or rebuild first.
Port already in use (EADDRINUSE)	Stop the previous process or change the port via env / bootstrap({ port }).
--container first run is very slow	Expected. It generates Dockerfile.development, builds the image, and pulls base layers. Subsequent runs are cached.