Logger for debugging

next-api-handler provides a logger interface that accepts any existed logger, also with a default logger that can be used to log messages to the console.

Logger Interface

next-api-handler can accept any logger solution (e.g. pino) that implements the following interface:

interface ApiLogger {
  debug: LogFunction;
  info: LogFunction;
  warn: LogFunction;
  error: LogFunction;
}

type LogFunction = (message?: string) => void;

To use a logger, you can pass it to the RouterBuilder constructor:

import { RouterBuilder } from 'next-api-handler';
import { logger } from '@/server/logger';

const router = new RouterBuilder({
  logger: myLogger,
});

Default Logger

next-api-handler also provides a default logger that can be used to log messages to the console, which will be used if no logger is passed to the RouterBuilder constructor.

When running locally in development mode, you may see messages similar to the following on console:

[next-api-handler] error 2022-11-29T14:15:30.828Z Caught errors from GET /api/after/simple with 0ms
[next-api-handler] info 2022-11-29T14:16:59.306Z Successfully handled GET /api/after/simple?id=123 with 0ms

Logger Options

This behavior could be amended by updating logger option

import { RouterBuilder } from 'next-api-handler';

const router = new RouterBuilder({
  loggerOptions: {
    context: 'my-context',
    level: 'info',
  },
});

where context is the context of the logger shown in console, and level is the log level.

level satisfies type LoggerLevel and has available ordered options silent, debug, info, warn, error such that

• if level is silent, no logs will be triggered
• otherwise only the methods itself & after will be triggered e.g. when level="warn", only logger.warn & logger.error will show on the console

Default Logger Options

By default, level is pre-configured based on different Node running environments

# when running in development i.e. NODE_ENV=development
level="info"

# when running in production i.e. NODE_ENV=production
level="error"

# when running tests i.e. NODE_ENV=test
level="silent"