4.0 KiB
process-warning
A small utility for generating consistent warning objects across your codebase. It also exposes a utility for emitting those warnings, guaranteeing that they are issued only once (unless configured otherwise).
This module is used by the Fastify framework and it was called fastify-warning prior to version 1.0.0.
Install
npm i process-warning
Usage
The module exports a builder function that returns a utility for creating warnings and emitting them.
const warning = require('process-warning')()
Methods
warning.create(name, code, message[, options])
name(string, required) - The error name, you can access it later witherror.name. For consistency, we recommend prefixing module error names with{YourModule}Warningcode(string, required) - The warning code, you can access it later witherror.code. For consistency, we recommend prefixing plugin error codes with{ThreeLetterModuleName}_, e.g.FST_. NOTE: codes should be all uppercase.message(string, required) - The warning message. You can also use interpolated strings for formatting the message.options(object, optional) - Optional options with the following properties:unlimited(boolean, optional) - Should the warning be emitted more than once? Defaults tofalse.
warning.createDeprecation(code, message[, options])
This is a wrapper for warning.create. It is equivalent to invoking
warning.create with the name parameter set to "DeprecationWarning".
Deprecation warnings have extended support for the Node.js CLI options:
--throw-deprecation, --no-deprecation, and --trace-deprecation.
warning.emit(code [, a [, b [, c]]])
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 at least once.
code(string, required) - The warning code you intend to emit.[, a [, b [, c]]](any, optional) - Parameters for string interpolation.
const warning = require('process-warning')()
warning.create('FastifyWarning', 'FST_ERROR_CODE', 'message')
warning.emit('FST_ERROR_CODE')
How to use an interpolated string:
const warning = require('process-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('process-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
How to use an unlimited warning:
const warning = require('process-warning')()
warning.create('FastifyWarning', 'FST_ERROR_CODE', 'Hello %s', { unlimited: true })
warning.emit('FST_ERROR_CODE', 'world') // will be emitted
warning.emit('FST_ERROR_CODE', 'world') // will be emitted again
Suppressing warnings
It is possible to suppress warnings by utilizing one of node's built-in warning suppression mechanisms.
Warnings can be suppressed:
- by setting the
NODE_NO_WARNINGSenvironment variable to1 - by passing the
--no-warningsflag to the node process - by setting 'no-warnings' in the
NODE_OPTIONSenvironment variable
For more information see node's documentation.
License
Licensed under MIT.