TypeScript is a superset of JavaScript that provides developers with a type system and other features that make writing large-scale applications more manageable. Docker is a containerization platform that enables developers to package their applications into a portable container, ensuring that they can run consistently across different environments.

Combining TypeScript and Docker can help developers to streamline their development workflow, ensuring that their code is consistent and can be easily deployed to production. In this short tutorial, we'll explore how to use TypeScript and Docker together.


Setup TypeScript Project

The first step is to create a TypeScript project. You can do this by running the following commands in your terminal:

mkdir my-project
cd my-project
npm init -y
npm install typescript --save-dev

This will create a new project directory, initialize a package.json file, and install TypeScript as a dev dependency.


Create a Dockerfile

Next, we'll need to create a Dockerfile that will define how our application will be packaged. A simple Dockerfile for a TypeScript application might look like this:

# Use an official Node.js runtime as a parent image
FROM node:14

# Set the working directory to /app
WORKDIR /app

# Copy package.json and package-lock.json to the working directory
COPY package*.json ./

# Install dependencies
RUN npm install

# Copy the rest of the application code to the working directory
COPY . .

# Build TypeScript code
RUN npm run build

# Expose port 3000
EXPOSE 3000

# Start the application
CMD [ "npm", "start" ]
  1. This Dockerfile does the following:
  2. Uses the official Node.js runtime as a parent image.
  3. Sets the working directory to /app.
  4. Copies the package.json and package-lock.json files to the working directory.
  5. Installs the dependencies.
  6. Copies the rest of the application code to the working directory.
  7. Builds the TypeScript code.
  8. Exposes port 3000 (the port on which our application will run).
  9. Starts the application.

Build and Run the Docker Image

Now that we have a Dockerfile, we can build a Docker image of our application. To do this, run the following command in your terminal:

docker build -t my-app .

This command will build a Docker image named "my-app" using the Dockerfile in the current directory (denoted by the "." at the end of the command). Once the build is complete, we can run the image using the following command: 

docker run -p 3000:3000 my-app

This command will start a Docker container running our application, mapping port 3000 inside the container to port 3000 on our host machine. Now, we can access our application by navigating to http://localhost:3000 in our web browser.

And that's it! By combining TypeScript and Docker, we can ensure that our applications are consistent and easily deployable across different environments.


Mounting Source Code in Development Mode

During development, we don't want to rebuild the Docker image every time we make a change to the code. Instead, we can use Docker's volume feature to mount the local source code into the container.

To do this, we need to modify the Docker run command to include a volume flag that maps our local code to the container's code. For example:

docker run -p 3000:3000 -v $(pwd):/app my-app

This command maps the current directory (denoted by $(pwd)) to the /app directory in the container. This means that any changes we make to the code on our local machine will be immediately reflected in the container.


Using Docker Compose

If our application has multiple services, we can use Docker Compose to define and manage the containers for each service. Docker Compose allows us to define the services and their dependencies in a YAML file, making it easier to manage and scale our application.

For example, a Docker Compose file for a TypeScript application might look like this:

version: '3'
services:
  app:
    build: .
    ports:
      - "3000:3000"
    volumes:
      - .:/app
    command: npm run start

This file defines a single service named "app" that builds the image using the Dockerfile in the current directory, maps port 3000, mounts the current directory to the /app directory in the container, and runs the command "npm run start" to start the application.

To start the services defined in the Docker Compose file, run the following command:

docker-compose up

This command will start all the services defined in the Docker Compose file.

In conclusion, combining TypeScript and Docker can help developers to streamline their development workflow, ensure consistency, and simplify deployment to production. By following the steps outlined in this tutorial, you should be able to get started with TypeScript and Docker quickly and easily.