How do you actually test a custom logger with this?

[slidenerd]

• The examples simple create a stream and pass that to the pino instance and boom it is done
• But what if your logger has a lot of stuff configured on it and you want to test it

import { randomUUID } from "node:crypto";
import { type LoggerOptions, pino } from "pino";
import { type Options, pinoHttp } from "pino-http";

const loggerOptions: LoggerOptions = {
	enabled: process.env.LOGGING_ENABLED === "true",
	formatters: {
		level(label) {
			return { level: label };
		},
	},
	level: process.env.LOGGING_LEVEL || "info",
	name: process.env.APP_NAME || "app",
	redact: {
		censor: "**REDACTED**",
		paths:
			process.env.LOGGING_REDACTED_KEYS?.split(",")
				.map((key) => key.trim())
				.filter((key) => key) || [],
	},
	serializers: pino.stdSerializers,
	timestamp: pino.stdTimeFunctions.isoTime,
	transport:
		process.env.NODE_ENV !== "production"
			? {
					target: "pino-pretty",
					options: {
						colorize: true,
						translateTime: "UTC:yyyy-mm-dd HH:MM:ss.l o",
					},
				}
			: undefined,
};

export const logger = pino(loggerOptions);

export const createChildLogger = (context: Record<string, unknown>) => {
	return logger.child(context);
};

const httpLoggerOptions: Options = {
	customLogLevel(req, res, err) {
		if (res.statusCode >= 500) {
			return "error";
		}
		if (res.statusCode >= 400) {
			return "warn";
		}
		return "info";
	},
	genReqId: (req) => {
		return req.headers["x-request-id"] || randomUUID();
	},
	logger,
};

export const httpLogger = pinoHttp(httpLoggerOptions);

• Take this logger/index.ts file for example that exports both a pino logger and a pino-http logger
• If i wanted to test this, where do I pass that stream?

[ruddenchaux]

I usually use a function that encapsulates all the logic and this helps to have a more testable code. In that case you could pass the stream to the function, as an optional parameter, and, if present, propagate it to pino.