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winston-json-formatter

library0.10.0jsnpmunverified

A JSON and console formatter for winston@3, version 0.10.0. Enables structured logging with configurable output formats (JSON or console) and automatic hostname detection. Supports direct error object logging, custom metadata, and environment-based format switching via NODE_ENV. Released under ISC license, maintained on GitHub by amida-tech. Differentiates from other formatters by offering a simple configuration interface inspired by winston's format system, though it uses the legacy `logger.format` assignment rather than the modern `format` pipeline.

devops

npm install winston-json-formatter

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · WINSTON-JSON-FORMA

winston-json-formatter

devopsjavascriptv0.10.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

configuredFormatter

✓ import { configuredFormatter } from 'winston-json-formatter'

✗ const configuredFormatter = require('winston-json-formatter')

Package is ESM-only since v0.10.0; CommonJS require will fail.

default

✓ import configuredFormatter from 'winston-json-formatter'

✗ import { configuredFormatter } from 'winston-json-formatter'

Only a default export is provided; named import will result in undefined.

configuredFormatter (TypeScript)

✓ import configuredFormatter from 'winston-json-formatter'

✗ import { configuredFormatter } from 'winston-json-formatter'

TypeScript users must use default import; types are included.

Sets up a Winston logger with JSON formatting using winston-json-formatter, demonstrating basic logging and error object handling.

import winston from 'winston'; import configuredFormatter from 'winston-json-formatter'; const logger = winston.createLogger({ level: 'silly', transports: [new winston.transports.Console()] }); const options = { service: 'test-service', logger: 'Winston-JSON-Formatter', version: '1.0.0', typeFormat: 'json' }; logger.format = configuredFormatter(options); logger.info('Hello, world!'); logger.error(new Error('Something broke'));

Debug

Known issues

breakingPackage migrated to ESM-only in v0.10.0; CommonJS require() will fail.

fix

Use import syntax or dynamic import().

affects: >=0.10.0

gotchaThe formatter is assigned to logger.format, overriding the default format. Do not use winston.format.combine() with this package.

fix

Set logger.format = configuredFormatter(options) directly.

affects: *

gotchaNODE_ENV=dev or NODE_ENV=development forces console format regardless of options.typeFormat.

fix

Set NODE_ENV to production or another value to use JSON format.

affects: *

deprecatedThe 'node_env' option is misnamed (lowercase with underscore) compared to standard NODE_ENV.

fix

Use the upper-case environment variable NODE_ENV instead.

affects: *

Errors

Common errors & fixes

Cannot find module 'winston-json-formatter'

Package not installed or wrong import syntax in CommonJS.

fix

npm install winston-json-formatter && use import configuredFormatter from 'winston-json-formatter'.

TypeError: configuredFormatter is not a function

Using named import { configuredFormatter } instead of default import.

fix

Change to import configuredFormatter from 'winston-json-formatter'.

TypeError: Cannot assign to read only property 'format' of object '#<Logger>'

Logger format is frozen in winston@3; must assign during creation.

fix

Set logger.format = configuredFormatter(options) before any logging calls.

Upgrade

Version history

0.10.0latest on npm

Audit

Dependencies

winstonrequiredpeer dependency for logger and transports

Agent activity

7 hits · last 30 days

node

Resources

githubhttps://github.com/amida-tech/winston-json-formatter ↗

packagewinston-json-formatter ↗

homepagehttps://github.com/amida-tech/winston-json-formatter#readme ↗