@oxy2/console-logger

@oxy2/console-logger

Replaces console.log() with a contextual JSON logger.

This module only works in node, not the browser.

Quick start

import { initLogger } from "@oxy2/console-logger";

// All console logs from now on will be JSON data with `level` and `time` properties
initLogger();
console.log({ x: 123 });
console.error({ error: "something happened" });
// => {"level":30,"time":1621043684459,"x":123}
// => {"level":50,"time":1621043684459,"error":"something happened"}

// Calling `addToLoggerContext()` will add data to all further logs in the current synchronous execution
import { addToLoggerContext } from "@oxy2/console-logger";
serverMiddleware((path) => addToLoggerContext({ path }));
onGet("/hello", () => console.log("Hello, world!"));
// => {"level":30,"time":1621043684459,"msg":"Hello, world!","path":"/hello"}

// Pass `useDevLogger` during development to print pretty logs
initLogger({ useDevLogger: true });
console.log("Hello, world!", { path: "/hello" });
// => (i) Hello, world! { path: "/hello" }

// Pass `useConsole` to avoid modifying the global console
import { logger } from "@oxy2/console-logger";
initLogger({ useConsole: false });
logger.info("Hello, world!", { path: "/hello" });
// => {"level":30,"time":1621043684459,"msg":"Hello, world!","path":"/hello"}

Notes

• The level numbers start from 20 for compatibility with most other loggers (Bunyan, Pino, etc.) like so:
  • debug = 20
  • info = 30
  • warn = 40
  • error = 50
• "Synchronous execution" referred to above includes awaiting promises. Asynchronous executions are started when callbacks are called to things like setTimeout(), http.createServer(), etc. You can read more about this on the node documentation.
• The default logger implementation is Pino. This logger has a few default behaviours to be aware of:
  • All log levels (even error) are printed to STDOUT when run in production mode.
  • debug logs are ignored by the default logger implementation when run in production mode (nothing is printed to STDOUT).

Contributing

See CONTRIBUTING.md for instructions how to develop locally and make changes.