docs: add initial readme

Release-As: 0.1.0

Author: xseman

README.md

@@ -0,0 +1,72 @@
+# log4js layout - json
+
+Simple json layouy module for [log4js][log4js_github].
+
+[log4js_github]: https://log4js-node.github.io/log4js-node/
+
+## Installation
+
+### npm registry
+
+```sh
+npm install log4js-layout-json
+```
+
+## Example Output
+
+Output:
+
+```plain
+{"time":"2024-05-11T18:18:34.266Z","category":"default","level":"INFO","msg":"Initializing DB connection"}
+```
+
+Adding context:
+
+```ts
+log.addContext("user", "john");
+```
+
+```plain
+{"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
+
+```ts
+import log4js from "log4js";
+import jsonLayout from "log4js-json-layout";
+
+log4js.addLayout("json", jsonLayout);
+```
+
+minimal:
+
+```ts
+log4js.configure({
+	appenders: {
+		out: {
+			type: "stdout",
+			layout: {
+				type: "json",
+			},
+		},
+	},
+	categories: {
+		default: {
+			level: "debug",
+			appenders: ["out"],
+		},
+	},
+});
+```