karma-webpack.js

/* eslint-disable
  max-len,
  no-console,
  func-style,
*/

var os = require('os')
var _ = require('lodash')
var path = require('path')
var async = require('async')
var webpackDevMiddleware = require('webpack-dev-middleware')
var webpack = require('webpack')
var SingleEntryDependency = require('webpack/lib/dependencies/SingleEntryDependency')

var blocked = []
var isBlocked = false

var escapeRegExp = function(str) {
  // See details here https://stackoverflow.com/questions/3446170/escape-string-for-use-in-javascript-regex
  return str.replace(/[-[\]/{}()*+?.\\^$|]/g, '\\$&')
}

function Plugin(
  /* config.webpack */ webpackOptions,
  /* config.webpackServer */ webpackServerOptions,
  /* config.webpackMiddleware */ webpackMiddlewareOptions,
  /* config.basePath */ basePath,
  /* config.files */ files,
  /* config.frameworks */ frameworks,
  /* config.singleRun */ singleRun,
  customFileHandlers,
  emitter
) {
  webpackOptions = _.clone(webpackOptions) || {}
  webpackMiddlewareOptions = _.clone(webpackMiddlewareOptions || webpackServerOptions) || {}

  var applyOptions = Array.isArray(webpackOptions) ? webpackOptions : [webpackOptions]
  var includeIndex = applyOptions.length > 1

  applyOptions.forEach(function(webpackOptions, index) {
    // The webpack tier owns the watch behavior so we want to force it in the config
    webpackOptions.watch = !singleRun

    // Webpack 2.1.0-beta.7+ will throw in error if both entry and plugins are not specified in options
    // https://github.com/webpack/webpack/commit/b3bc5427969e15fd3663d9a1c57dbd1eb2c94805
    if (!webpackOptions.entry) {
      webpackOptions.entry = function() {
        return {}
      }
    };

    if (!webpackOptions.output) {
      webpackOptions.output = {}
    };

    // When using an array, even of length 1, we want to include the index value for the build.
    // This is due to the way that the dev server exposes commonPath for build output.
    var indexPath = includeIndex ? `${index}/` : ''
    var publicPath = indexPath !== '' ? `${indexPath}/` : ''

    // Must have the common _karma_webpack_ prefix on path here to avoid
    // https://github.com/webpack/webpack/issues/645
    webpackOptions.output.path = path.join(os.tmpdir(), '_karma_webpack_', indexPath, '/')
    webpackOptions.output.publicPath = path.join(os.tmpdir(), '_karma_webpack_', publicPath, '/')
    webpackOptions.output.filename = '[name]'
    if (includeIndex) {
      webpackOptions.output.jsonpFunction = `webpackJsonp${index}`
    }
    webpackOptions.output.chunkFilename = '[id].bundle.js'
  })

  this.emitter = emitter
  this.wrapMocha = frameworks.indexOf('mocha') >= 0 && includeIndex
  this.optionsCount = applyOptions.length
  this.files = []
  this.basePath = basePath
  this.waiting = []

  var compiler

  try {
    compiler = webpack(webpackOptions)
  } catch (e) {
    console.error(e.stack || e)
    if (e.details) {
      console.error(e.details)
    }
    throw e
  }

  var applyPlugins = compiler.compilers || [compiler]

  applyPlugins.forEach(function(compiler) {
    compiler.plugin('this-compilation', function(compilation, params) {
      compilation.dependencyFactories.set(SingleEntryDependency, params.normalModuleFactory)
    })
    compiler.plugin('make', this.make.bind(this))
  }, this);

  ['invalid', 'watch-run', 'run'].forEach(function(name) {
    compiler.plugin(name, function(_, callback) {
      isBlocked = true

      if (typeof callback === 'function') {
        callback()
      }
    })
  })

  compiler.plugin('done', function(stats) {
    var applyStats = Array.isArray(stats.stats) ? stats.stats : [stats]
    var assets = []
    var noAssets = false

    applyStats.forEach(function(stats) {
      stats = stats.toJson()

      assets.push(...stats.assets)
      if (stats.assets.length === 0) {
        noAssets = true
      }
    })

    if (!this.waiting || this.waiting.length === 0) {
      this.notifyKarmaAboutChanges()
    }

    if (this.waiting && !noAssets) {
      var w = this.waiting

      this.waiting = null
      w.forEach(function(cb) {
        cb()
      })
    }

    isBlocked = false
    for (var i = 0; i < blocked.length; i++) {
      blocked[i]()
    }
    blocked = []
  }.bind(this))
  compiler.plugin('invalid', function() {
    if (!this.waiting) {
      this.waiting = []
    }
  }.bind(this))

  webpackMiddlewareOptions.publicPath = path.join(os.tmpdir(), '_karma_webpack_', '/')
  var middleware = this.middleware = new webpackDevMiddleware(compiler, webpackMiddlewareOptions)

  customFileHandlers.push({
    urlRegex: new RegExp(`^${escapeRegExp(webpackMiddlewareOptions.publicPath)}.*`),
    handler(req, res) {
      middleware(req, res, function() {
        res.statusCode = 404
        res.end('Not found')
      })
    }
  })

  emitter.on('exit', function(done) {
    middleware.close()
    done()
  })
}

Plugin.prototype.notifyKarmaAboutChanges = function() {
  // Force a rebuild
  this.emitter.refreshFiles()
}

Plugin.prototype.addFile = function(entry) {
  if (this.files.indexOf(entry) >= 0) {
    return
  }
  this.files.push(entry)

  return true
}

Plugin.prototype.make = function(compilation, callback) {
  async.forEach(this.files.slice(), function(file, callback) {
    var entry = file

    if (this.wrapMocha) {
      entry = `${require.resolve('./mocha-env-loader')}!${entry}`
    }

    var dep = new SingleEntryDependency(entry)

    compilation.addEntry('', dep, path.relative(this.basePath, file).replace(/\\/g, '/'), function(err) {
      // If the module fails because of an File not found error, remove the test file
      if (dep.module && dep.module.error &&
        dep.module.error.error &&
        dep.module.error.error.code === 'ENOENT') {
        this.files = this.files.filter(function(f) {
          return file !== f
        })
        this.middleware.invalidate()
      }
      callback(err)
    }.bind(this))
  }.bind(this), callback)
}

Plugin.prototype.readFile = function(file, callback) {
  var middleware = this.middleware
  var optionsCount = this.optionsCount

  var doRead = function() {
    if (optionsCount > 1) {
      async.times(optionsCount, function(idx, callback) {
        middleware.fileSystem.readFile(path.join(os.tmpdir(), '_karma_webpack_', String(idx), file.replace(/\\/g, '/')), callback)
      }, function(err, contents) {
        if (err) {
          return callback(err)
        };
        contents = contents.reduce(function(arr, x) {
          if (!arr) {
            return [x]
          };
          arr.push(new Buffer('\n'), x)

          return arr
        }, null)
        callback(null, Buffer.concat(contents))
      })
    } else {
      try {
        var fileContents = middleware.fileSystem.readFileSync(path.join(os.tmpdir(), '_karma_webpack_', file.replace(/\\/g, '/')))

        callback(undefined, fileContents)
      } catch (e) {
        // If this is an error from `readFileSync` method, wait for the next tick.
        // Credit #69 @mewdriller
        if (e.code === 'ENOENT') {
          // eslint-disable-line quotes
          this.waiting = [process.nextTick.bind(process, this.readFile.bind(this, file, callback))]

          // throw otherwise
        } else {
          callback(e)
        }
      }
    }
  }.bind(this)

  if (!this.waiting) {
    doRead()
  } else {
    // Retry to read once a build is finished
    // do it on process.nextTick to catch changes while building
    this.waiting.push(process.nextTick.bind(process, this.readFile.bind(this, file, callback)))
  }
}

function createPreprocesor(/* config.basePath */ basePath, webpackPlugin) {
  return function(content, file, done) {
    if (webpackPlugin.addFile(file.originalPath)) {
      // recompile as we have an asset that we have not seen before
      webpackPlugin.middleware.invalidate()
    }

    // read blocks until bundle is done
    webpackPlugin.readFile(path.relative(basePath, file.originalPath), function(err, content) {
      if (err) {
        throw err
      }

      done(err, content && content.toString())
    })
  }
}

function createWebpackBlocker() {
  return function(request, response, next) {
    if (isBlocked) {
      blocked.push(next)
    } else {
      next()
    }
  }
}

module.exports = {
  webpackPlugin: ['type', Plugin],
  'preprocessor:webpack': ['factory', createPreprocesor],
  'middleware:webpackBlocker': ['factory', createWebpackBlocker]
}