@shopify/sewing-kit/lib/packages/fail-on-unexpected-module-shaking-plugin/index.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
const pluginName = 'FailOnUnexpectedModuleShakingPlugin';

function isExcluded(module, exclude = []) {
  return exclude.find(excludePath => typeof excludePath === 'string' ? module === excludePath : excludePath.test(module));
}

function isSideEffectImport(module) {
  const {
    buildMeta
  } = module;

  if (Array.isArray(buildMeta.providedExports) && buildMeta.providedExports.length > 0) {
    return false;
  }

  return module.reasons.every(reason => reason.dependency.constructor.name === 'HarmonyImportSideEffectDependency');
}

function isSideEffectFree(module) {
  // `webpack/lib/optimize/SideEffectsFlagPlugin` sets this value.
  return module.factoryMeta.sideEffectFree === true;
}

function findUnexpectedRemovals(compilation, {
  exclude
}) {
  const context = compilation.options.context;
  const removed = compilation.modules.filter(module => Boolean(module.resource)).filter(isSideEffectImport).filter(isSideEffectFree).map(module => module.resource.replace(new RegExp(`^${context}/`), './'));
  return removed.filter(module => !isExcluded(module, exclude));
}

exports.findUnexpectedRemovals = findUnexpectedRemovals;

class FailOnUnexpectedModuleShakingPlugin {
  constructor(options = {}) {
    this.options = {
      exclude: options.exclude || []
    };
  }

  apply(compiler) {
    compiler.hooks.compilation.tap(pluginName, compilation => {
      compilation.hooks.afterOptimizeTree.tap(pluginName, () => {
        const removed = findUnexpectedRemovals(compilation, this.options);

        if (removed.length > 0) {
          const moduleNames = removed.sort().join('",\n    "');
          compilation.errors.push(`webpack has removed these modules:\n    "${moduleNames}"\n\n` + '• If a module is necessary for production, preserve it by adding it to package.json#sideEffects (for more information, see https://github.com/webpack/webpack/tree/master/examples/side-effects)\n' + `• If a module can be safely removed, add it to ${pluginName}'s 'exclude' list`);
        }
      });
    });
  }

}

exports.FailOnUnexpectedModuleShakingPlugin = FailOnUnexpectedModuleShakingPlugin;