log4js layout - json

Simple json layout module for log4js.

Installation

npm registry

npm install log4js-layout-json

Example Output

Output:

{"time":"2024-05-11T18:18:34.266Z","category":"default","level":"INFO","msg":"Initializing DB connection"}

Adding context:

log.addContext("user", "john");

{"time":"2024-05-11T18:19:34.266Z","category":"default","level":"INFO","msg":"Initializing DB connection","user":"john"}

Usage

Set the layout type to json.

Each log object contains the following properties:

• time - time in ISO 8601 format
• category - specified when log4js is initialized
• msg - if the log message is a string, otherwise omitted
• level - level in human readable format

Example configuration

import log4js from "log4js";
import { layout as jsonLayout } from "log4js-json-layout";

log4js.addLayout("json", jsonLayout);

minimal:

log4js.configure({
	appenders: {
		out: {
			type: "stdout",
			layout: {
				type: "json",
				includeFileName: true,
				includeFunctionName: true,
			},
		},
	},
	categories: {
		default: {
			level: "debug",
			appenders: ["out"],
		},
	},
});