> For the complete documentation index, see [llms.txt](https://quinck.gitbook.io/multijet/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://quinck.gitbook.io/multijet/configuration/microservices-and-libs.md).

# Microservices and libs

Since we are in a **Node.js multiproject**, each lib or microservice has a `package.json` file. As in any other Node project, this file contains all the package's informations and scripts.

## Microservice configuration

Every microservice's `package.json` file is similar and contains the same scripts. The main properties that are different are the `name` and `dependencies`.

Example:

{% code title="package.json" %}

```json
{
    "name": "@microservices/hello-service",
    "private": true,
    "version": "0.0.1",
    "scripts": {
        "build": "node ../../configs/esbuild/esbuild.config.js lambda",
        "build:debug": "node ../../configs/esbuild/esbuild.config.js",
        "lint": "eslint ./src",
        "typecheck": "tsc",
        "clean": "rm -rf dist .turbo node_modules"
    },
    "dependencies": {
        "@fastify/aws-lambda": "^3.2.0",
        "@libs/fastify-utils": "^0.0.1",
        "@libs/utils": "^0.0.1"
    }
}
```

{% endcode %}

As you can see there are serveral scripts defined in each microservice:

* **typecheck**: this script runs `tsc` **without emitting files** (see [TypeScript project configuration](/multijet/configuration/project-configuration.md#typescript) for more information). This will simply check for type errors.
* **build**: this will run a global **esbuild** configuration file to bundle the **entire microservice in a single file** (head to [Build configuration](/multijet/configuration/build-configuration.md) to learn more)
* **lint**: runs `eslint` on the microservice's source directory. This will use the project root's `.eslint.yml` file

## Lib configuration

{% code title="package.json" %}

```json
{
    "name": "@libs/utils",
    "private": true,
    "version": "0.0.1",
    "types": "src/index.ts",
    "main": "src/index.ts",
    "scripts": {
        "typecheck": "tsc",
        "lint": "eslint .",
        "test": "mocha",
        "clean": "rm -rf .turbo node_modules"
    },
    "dependencies": {
        "joi": "^17.8.3",
        "pino": "^8.11.0"
    }
}

```

{% endcode %}

One important thing that is different from microservice is the `main` and `types` properties. These two points to the TypeScript entrypoint of the lib (usually `src/index.ts`) in order to **resolve the lib as a dependency for a microservice** (in this way esbuild can build and include the lib in the bundle of a microservice that uses that lib).

Thanks to esbuild, libs **do not have a build script**. This makes not possibile to build a only the single lib by default.