What is metro-config?
The metro-config package provides utilities to configure and customize Metro, which is a JavaScript bundler for React Native. It allows developers to modify the default configuration of Metro to suit their project's specific needs.
What are metro-config's main functionalities?
Default Configuration
Retrieve the default Metro configuration which can be used as a starting point for customizing the bundler settings.
const { getDefaultConfig } = require('metro-config');
async function getConfig() {
const config = await getDefaultConfig(__dirname);
return config;
}
Merge Configurations
Combine the default Metro configuration with custom settings to create a new configuration object.
const { mergeConfig } = require('metro-config');
const defaultConfig = await getDefaultConfig(__dirname);
const customConfig = {
resolver: {
sourceExts: ['jsx', 'js', 'ts', 'tsx'],
},
};
const mergedConfig = mergeConfig(defaultConfig, customConfig);
Load Config
Load the Metro configuration from a project, which can include the default settings, settings from a metro.config.js file, or settings from package.json.
const { loadConfig } = require('metro-config');
async function getConfig() {
const config = await loadConfig();
return config;
}
Other packages similar to metro-config
webpack
Webpack is a powerful module bundler for JavaScript applications. It offers a rich plugin interface and is highly configurable, similar to Metro, but it is more commonly used in web development rather than React Native.
rollup
Rollup is another module bundler that focuses on producing efficient bundles using a technique called 'tree shaking' to eliminate unused code. It is simpler and more lightweight compared to Metro, and it is also more geared towards web development.
parcel
Parcel is a web application bundler that offers a zero-configuration experience. It is different from Metro in that it is optimized for web development and provides out-of-the-box support for many web assets without the need for additional plugins or configuration.
browserify
Browserify is a tool for bundling JavaScript files for usage in the browser. It allows you to use require('modules') in the browser by bundling up all of your dependencies. It is less feature-rich compared to Metro and is primarily focused on bundling for the web rather than React Native.