/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file at
 * https://github.com/facebookincubator/create-react-app/blob/master/LICENSE
 */

// This Webpack plugin ensures `npm install <library>` forces a project rebuild.
// We’re not sure why this isn't Webpack's default behavior.
// See https://github.com/facebookincubator/create-react-app/issues/186.

module.exports = class WatchMissingNodeModulesPlugin {
  constructor (nodeModulesPath) {
    this.nodeModulesPath = nodeModulesPath
  }

  apply (compiler) {
    compiler.plugin('emit', (compilation, callback) => {
      var missingDeps = compilation.missingDependencies
      var nodeModulesPath = this.nodeModulesPath

      // If any missing files are expected to appear in node_modules...
      if (missingDeps.some(file => file.indexOf(nodeModulesPath) !== -1)) {
        // ...tell webpack to watch node_modules recursively until they appear.
        compilation.contextDependencies.push(nodeModulesPath)
      }

      callback()
    })
  }
}
