start-app

• Serves an application from a file
• Reads a config from a file and passes it to the application
• Logs clearly and passes the logger to the application

Installation

npm:

npm i @samtayl/start-app

yarn:

yarn i @samtayl/start-app

Usage

Create an app.js file in the package directory. This must export a function which returns a request handler for the server.

export default function() {
  return function(req, res) {
    res.end('Hello, World! :3');
  };
};

Run start-app to start the server and serve the app.

By default, the server listens at http://127.0.0.1:8000.

Configuration

Configuring your app

Create a config.json file in the package directory. This object will be passed to the exported function in the app.js file.

{
  "greeting": "Hello, World! :3"
}

export default function(options) {
  return function(req, res) {
    res.end(options.greeting); // "Hello, World! :3"
  };
};

Configuring start-app

These config.json properties will change the behaviour of start-app:

| config.json property | type | format | default | description | | ---------------------- | -------- | ----------------------------------------------------------------------- | ------------- | ----------------------------------------------- | | appPath | string | A pathname relative to where the start-app command is ran. | "app.js" | The pathname of the file which your app is in. | | logLevel | string | One of 'silly', 'debug', 'verbose', 'http', 'info', 'warn', or 'error'. | "info" | The log level which should be displayed. | | port | number | A valid port. | 8000 | The port which the server should listen on. | | hostname | string | A valid hostname. | "127.0.0.1" | The hostname which the server should listen on. |

CLI options and environment variables

start-app uses convict to validate it's configuration and to enable a hierarchy of configuration methods. As such, the previously listed config.json properties are also available as the following command line arguments and environment variables:

| config.json property | command line argument | environment variable | | ---------------------- | --------------------- | -------------------- | | appPath | --appPath | APP_PATH | | logLevel | --logLevel | LOG_LEVEL | | port | --port | PORT | | hostname | --hostname | HOSTNAME |

Lastly, the path of the config file can also be changed:

| command line argument | environment variable | format | default | description | | --------------------- | -------------------- | ------------------------------------------------------------ | --------------- | ------------------------------------------------- | | --configPath | CONFIG_PATH | A pathname relative to where the start-app command is ran. | "config.json" | The pathname of the file which your config is in. |

Custom config schema

Create a configSchema.js file. This must export a convict instance as demonstrated by their documentation.

import convict from 'convict';

export default convict({
  greeting: {
    doc: 'The greeting to give',
    format: String,
    default: 'Hello. World. :|',
    env: 'GREETING',
    arg: 'greeting',
  },
});

Your configuration in config.json will now be validated against this schema. You may override the config.json properties listed above to change default values or command line argument and environment variable names.

Logging

The logger used to output from start-app will also be passed to your app. It is a winston instance.

export default function(options, logger) {
  return function(req, res) {
    logger.info("Hello, Console! :[]");

    res.end("Hello, World! :3");
  };
};