babel-plugin-js-logger

1.0.17 verified Sat Apr 25 auth: no javascript

Babel plugin that automatically inserts a logger declaration (via js-logger) at the top of every transpiled JavaScript file, enabling consistent logging across backend and frontend projects. Current stable version: 1.0.17. Maintained as of early 2021, with infrequent updates. Key differentiators: automatic logger instantiation per file, configurable logger name formatting (project/level/separator/extensions), and support for both Babel standalone and Webpack. Alternative to manual logger setup in each file. Note: requires js-logger as a peer dependency and Babel as a build tool.

Common errors

error Module not found: Error: Can't resolve 'js-logger' ↓

cause js-logger is not installed or not in node_modules.

fix

Install js-logger as a dependency: npm install js-logger --save

error Error: Cannot find module 'babel-plugin-js-logger' ↓

cause The plugin is not installed or not listed in .babelrc plugins correctly.

fix

Install the plugin: npm install babel-plugin-js-logger --save-dev, then add 'js-logger' to .babelrc plugins array.

error TypeError: require(...).useDefaults is not a function ↓

cause js-logger is not initialized properly.

fix

Call require('js-logger').useDefaults() before using the generated logger variables.

Warnings

gotcha With ES modules (import), the plugin's generated logger declaration may execute after imports due to hoisting, causing initialization order issues. ↓

fix Use a separate init file imported first, e.g., import './logger-init.js'; (see README).

gotcha The plugin automatically inserts a require() for js-logger even if it's not used, potentially causing tree-shaking to fail. ↓

fix Consider using manual logger setup if tree-shaking is critical.

gotcha The format option 'level' with negative values counts from the project root, which may include unwanted directories if project root detection fails. ↓

fix Test with your project structure and adjust level or extensions accordingly.

gotcha The plugin does not support TypeScript natively; TypeScript files must be handled by Babel with appropriate presets. ↓

fix Use @babel/preset-typescript and ensure the plugin runs after it.

Install

npm install babel-plugin-js-logger

yarn add babel-plugin-js-logger

pnpm add babel-plugin-js-logger

Imports

plugin
```
// Add 'js-logger' to .babelrc plugins array: { "plugins": ["js-logger"] }
```
The plugin is a Babel plugin, not a runtime import. It is configured in .babelrc or babel.config.js.
js-logger
```
import 'js-logger'; // or const Logger = require('js-logger');
```
js-logger is a runtime dependency that must be installed separately.
get
wrong
```
const logger = Logger.get('my:name'); // correct usage
```
correct
```
const logger = Logger.get('my:name');
```
The plugin automatically generates these calls per file. The factory option defaults to 'get'.

Quickstart

Installs and configures the plugin, initializes js-logger, and demonstrates automatic logger insertion per file.

// Install: npm install js-logger --save && npm install babel-plugin-js-logger --save-dev

// .babelrc
{
  "plugins": ["js-logger"]
}

// In your main entry point (e.g., main.js)
require('js-logger').useDefaults(); // initialize js-logger

// All other files will automatically have a logger variable
// Example: some/path/file.js
// The plugin inserts: const logger = require('js-logger').get('project:some:path:file');

// Use logger
logger.info('Hello from file!');