webpack-merge 5.9.0

Webpack-merge is a powerful tool designed for the purpose of merging and configuring Webpack objects. It provides a merge function that concatenates arrays and merges objects, creating a new object. If functions are encountered during merging, Webpack-merge executes them, runs the results through the algorithm, and then wraps the returned values within a function again. This makes Webpack-merge particularly useful for configuring Webpack, but it also has numerous applications beyond this.

In order to use Webpack-merge, you first need to import the module using const { merge } = require('webpack-merge');. Then, you can use the merge function to merge multiple objects together, resulting in a new combined object. A basic usage example is as follows:

const { merge } = require('webpack-merge');

// Merging object1, object2 and object3 into a new object
const output = merge(object1, object2, object3);

// Merging an array of objects. This works with all available functions
const output = merge([object1, object2, object3]);

For a more dynamic and complex Webpack configuration, you could use a switch case statement to merge different configurations depending on the provided mode:

const commonConfig = { ... };
const productionConfig = { ... };
const developmentConfig = { ... };

module.exports = (env, args) => {
  switch(args.mode) {
    case 'development':
      return merge(commonConfig, developmentConfig);
    case 'production':
      return merge(commonConfig, productionConfig);
    default:
      throw new Error('No matching configuration was found!');
  }
};

In this case, you would use webpack --mode development or webpack --mode production to choose your desired configuration.

Moreover, merge behavior can be customized at a per-field level using mergeWithCustomize.

The detailed documentation and code examples for Webpack-merge can be found directly in the package's README on its GitHub repository at https://github.com/survivejs/webpack-merge. Comprehensive explanations and additional use cases for Webpack-merge are featured in the book "SurviveJS - Webpack 5", accessible at http://survivejs.com/. Further support and expertise is also available through the consulting services provided by the creators and maintainers of Webpack-merge.