eazy-logger

Common errors

• ReferenceError: require is not defined in ES module scope

  cause Attempting to use `require()` in a JavaScript file that Node.js treats as an ES module (e.g., due to `"type": "module"` in `package.json` or a `.mjs` file extension).
  fix Either convert your project to CommonJS (remove `"type": "module"`), rename the file to `.cjs`, or use dynamic import with `const eazyLogger = await import('eazy-logger'); const { Logger } = eazyLogger;`.

• Property 'Logger' does not exist on type 'typeof import("/path/to/node_modules/eazy-logger/index")'.

  cause This error occurs in TypeScript when the `eazy-logger` package is imported without type definitions, and TypeScript cannot infer the structure of the module export.
  fix Create a `eazy-logger.d.ts` declaration file in your project to define the module's structure and the `Logger` class. See the 'Warnings' section for a basic example.

Warnings

• breaking The package is CommonJS-only and will not work directly with ES module `import` syntax in modern Node.js environments unless transpiled or dynamically imported. Attempting to `import` it will result in a runtime error.
  Fix: Ensure your project is configured for CommonJS, or use `const { Logger } = require('eazy-logger');` within an ES module via dynamic `await import('eazy-logger')` if applicable. For new projects, consider a modern logger with native ESM support.
• gotcha The project is in 'inactive' maintenance mode, meaning new features are unlikely, and compatibility with future Node.js versions or emerging JavaScript standards (like native TypeScript support) may not be guaranteed. While a security fix was applied recently, ongoing proactive maintenance is limited.
  Fix: Evaluate the long-term viability for new projects. For existing projects, be aware that future breaking Node.js changes might not be addressed.
• gotcha There are no official TypeScript type definitions shipped with the package, nor are there community-maintained types on `@types/eazy-logger`. This leads to type errors when used in TypeScript projects.
  Fix: Create a custom declaration file (e.g., `eazy-logger.d.ts`) to provide type information for the `Logger` class and its methods. An example would be `declare module 'eazy-logger' { class Logger { constructor(options: any); debug(...args: any[]): void; info(...args: any[]): void; warn(...args: any[]): void; error(...args: any[]): void; log(level: string, ...args: any[]): void; setOnce(key: string, value: any): Logger; } export { Logger }; }`

Install

• npm install eazy-logger npm
• yarn add eazy-logger yarn
• pnpm add eazy-logger pnpm

Imports

• Logger
  wrong:

  import { Logger } from 'eazy-logger';

  correct:

  const { Logger } = require('eazy-logger');

  This package is CommonJS-only and does not support ES module `import` syntax. The Logger class is accessed as a property of the main module export.
• logger
  wrong:

  import logger from 'eazy-logger';

  correct:

  const logger = require('eazy-logger').Logger({ /* config */ });

  The primary way to instantiate a logger is by calling the `Logger` factory method directly on the `require('eazy-logger')` return value.
• eazyLogger
  wrong:

  import * as eazyLogger from 'eazy-logger';

  correct:

  const eazyLogger = require('eazy-logger');
  const logger = eazyLogger.Logger({ /* config */ });

  For CommonJS, the entire module can be `require`d, and the `Logger` factory method is then accessed as a property of the imported object.

Quickstart

Demonstrates initializing the logger with a custom prefix and level prefixes, then using various log levels, string substitution, and setting options for a single log statement.

const { Logger } = require('eazy-logger');

const logger = Logger({
    prefix: "{blue:[}{magenta:easy-logger}{blue:] }",
    useLevelPrefixes: true
});

console.log('--- Standard Loggers ---');
logger.debug("Debugging Msg");
logger.info("Info statement");
logger.warn("A little warning with string %s", "substitution");
logger.error("An error occurred in file: {red:%s}", "/users/awesomedev/file.js");

console.log('\n--- String Substitution + Colours ---');
logger.log("error", "Use {green:built-in} %s", "String substitution");

console.log('\n--- Set Option for Next Log Only ---');
logger.setOnce("useLevelPrefixes", false).warn("This warning will not have a level prefix.");
logger.info("This info statement will use prefixes again.");