A small utility, used by Fastify itself, for generating consistent warning objects across your codebase and plugins. It also exposes a utility for emitting those warnings, guaranteeing that they are issued only once.
npm i fastify-warning
The module exports a builder function that returns a utility for creating warnings and emitting them.
const warning = require('fastify-warning')()
warning.create(name, code, message)
name
(string
, required) - The error name, you can access it later witherror.name
. For consistency, we recommend prefixing plugin error names withFastifWarning{YourPluginName}
code
(string
, required) - The warning code, you can access it later witherror.code
. For consistency, we recommend prefixing plugin error codes withFST_{YourPluginName}_
. NOTE: codes should be all uppercase.message
(string
, required) - The warning message. You can also use interpolated strings for formatting the message.
The utility also contains an emit
function that you can use for emitting the warnings you have previously created by passing their respective code. A warning is guaranteed to be emitted only once.
warning.emit(code [, a [, b [, c]]])
code
(string
, required) - The warning code you intend to emit.[, a [, b [, c]]]
(any
, optional) - Parameters for string interpolation.
const warning = require('fastify-warning')()
warning.create('FastifyWarning', 'FST_ERROR_CODE', 'message')
warning.emit('FST_ERROR_CODE')
How to use an interpolated string:
const warning = require('fastify-warning')()
warning.create('FastifyWarning', 'FST_ERROR_CODE', 'Hello %s')
warning.emit('FST_ERROR_CODE', 'world')
The module also exports an warning.emitted
Map, which contains all the warnings already emitted. Useful for testing.
const warning = require('fastify-warning')()
warning.create('FastifyWarning', 'FST_ERROR_CODE', 'Hello %s')
console.log(warning.emitted.get('FST_ERROR_CODE')) // false
warning.emit('FST_ERROR_CODE', 'world')
console.log(warning.emitted.get('FST_ERROR_CODE')) // true
Licensed under MIT.