fastify-prettier

A simple and lightweight beautifier plugin for Fastify.

fastify-prettier has support of beautifying payloads via query parameter to make responses more readable for developers/humans. Decoratorprettier can also be used anywhere in the fastify server as the content beautifier. The plugin itself uses prettier under the hood and is capable of parsing/formatting anything that prettier can.

fastify-prettier uses onSend fastify hook to beautify the response payload before it gets sent.

Note: streams and buffers are excluded in beautification process. Note: Fastify v4 support is shipped with v2.0.0.

Installation

$ npm install fastify-prettier

Usage

const fastify = require('fastify')()
const fastifyPrettier = require('fastify-prettier')

fastify.register(
  fastifyPrettier,
  {
    fallbackOnError: false
  }
)

fastify.get('/', (req, reply) => {
  const obj = {
    blackLivesMatter: true,
    favSinger: 'Ahmet Kaya'
  }

  reply
    .type('application/json')
    .send(obj)
})

fastify.listen(3000, () => {
  console.log('Fastify server is running on port: 3000')
})

// -------------------------------

// http://localhost:3000 -> will print out below result
/*
{"blackLivesMatter":true,"favSinger":"Ahmet Kaya"}
*/

// http://localhost:3000?pretty=true -> will print out below result
/*
{
  "blackLivesMatter": true,
  "favSinger": "Ahmet Kaya"
}
*/

You are allowed to change the query parameter option.

fastify.register(
  fastifyPrettier,
  {
    query: {
      name: 'beautify',
      value: 'yes'
    }
  }
)

// -------------------------------

// http://localhost:3000 -> will print out below result
/*
{"blackLivesMatter":true,"favSinger":"Ahmet Kaya"}
*/

// http://localhost:3000?beautify=yes -> will print out below result
/*
{
  "blackLivesMatter": true,
  "favSinger": "Ahmet Kaya"
}
*/

You can enable beautification for all outgoing payloads regardless the query parameter.

fastify.register(
  fastifyPrettier,
  {
    alwaysOn: true
  }
)

// -------------------------------

// http://localhost:3000 -> will print out below result
/*
{
  "blackLivesMatter": true,
  "favSinger": "Ahmet Kaya"
}
*/

Usage of Decorator

Feel free to use prettier decorator which beautifies the given content through the provided options whenever you need.

const response = fastify.prettier(
  // content type can be: boolean, number, object, array, string
  content,
  // prettier options (please see: prettierOpts)
  { parser: 'html', htmlWhitespaceSensitivity: 'ignore' }
)

Options

Name	Type	Default	Description
alwaysOn	boolean	false	To make all the payloads beautified in anyway
fallbackOnError	boolean	true	If something bad happens, send the original payload. If its false, an error will be thrown
overrideContentLength	boolean	true	Re-calculate content-length header for the beautified response
query	object	{ name: 'pretty', value: 'true' }	The query parameter that triggers the plugin to beautify the outgoing payload
enableOnSendHook	boolean	true	Allow the plugin to get injected into fastify onSend hook to beautify outgoing responses. The prettier decorator can still be used even if that option is disabled
prettierOpts	object	{ tabWidth: 2, parser: 'json-stringify' }	Please take a look prettier official documentation for more information