A small utility, used by Fastify itself, for generating consistent error objects across your codebase and plugins.

npm i fastify-error

The module exports a function that you can use consistent error objects, it takes 4 parameters.

createError(code, message [, statusCode [, Base]])

• code (string, required) - The error code, you can access it later with error.code. For consistency, we recommend to prefix the plugins error codes with FST_
• message (string, required) - The error message. You can also use interpolated strings for formatting the message.
• statusCode (number, optional) - The status code that Fastify will use if the error is sent via http.
• Base (Error, optional) - The base error object that will be used. (eg TypeError, RangeError)

const createError = require('fastify-error')
const CustomError = createError('ERROR_CODE', 'message')
console.log(new CustomError())

How to use a interpolated string:

const createError = require('fastify-error')
const CustomError = createError('ERROR_CODE', 'Hello %s')
console.log(new CustomError('world')) // error.message => 'Hello world'

Licensed under MIT.