NPM redux-logger Package

Redux Logger

Redux Logger is a helpful utility that logs actions and their resulting state changes in your Redux application. This can be very useful for debugging, tracing, and understanding the flow of data through your application.

Installation

To install Redux Logger, run the following command:

npm install redux-logger

Usage

Redux Logger is a middleware function that you can add to your Redux store. Once added, it will log every action and the resulting state changes to the console.

To add Redux Logger to your store, you can use the applyMiddleware function from the Redux store enhancer. For example:

import { createStore, applyMiddleware } from 'redux';
import logger from 'redux-logger';

const store = createStore(
  reducer,
  preloadedState,
  applyMiddleware(logger)
);

Configuration Options

Redux Logger has a number of configuration options that you can use to customize its behavior. These options are passed as the second argument to the logger function.

The following configuration options are available:

  • level: The logging level. Valid values are 'log', 'info', 'warn', and 'error'. Defaults to 'log'.
  • collapsed: Whether or not to collapse the state changes in the console. Defaults to false.
  • predicate: A function that returns true if the action should be logged. Defaults to () => true.
  • duration: The maximum duration of actions to log. Defaults to false (no limit).
  • timestamp: Whether or not to include a timestamp in the log. Defaults to false.
  • transformer: A function that transforms the state before it is logged. Defaults to state => state.

Best Practices

Here are some best practices for using Redux Logger:

  • Use Redux Logger only in development mode.
  • Configure the level option to 'info' or 'warn' to avoid logging too much information.
  • Use the collapsed option to collapse the state changes in the console.
  • Use the predicate option to filter out actions that you don’t want to log.
  • Use the duration option to limit the duration of actions to log.
  • Use the timestamp option to include a timestamp in the log.
  • Use the transformer option to transform the state before it is logged.

Examples

The following examples show you how to use Redux Logger in your application:

Example 1: Basic Usage

import { createStore, applyMiddleware } from 'redux';
import logger from 'redux-logger';

const store = createStore(
  reducer,
  preloadedState,
  applyMiddleware(logger)
);

Example 2: Configuring Redux Logger

import { createStore, applyMiddleware } from 'redux';
import logger from 'redux-logger';

const store = createStore(
  reducer,
  preloadedState,
  applyMiddleware(logger({ level: 'info', collapsed: true }))
);

Example 3: Using Redux Logger with a Transformer

import { createStore, applyMiddleware } from 'redux';
import logger from 'redux-logger';

const transformer = state => {
  return {
    ...state,
    todos: state.todos.map(todo => ({ ...todo, text: todo.text.toUpperCase() }))
  };
};

const store = createStore(
  reducer,
  preloadedState,
  applyMiddleware(logger({ transformer }))
);