Javascript 如何使量角器等待webpack开发服务器启动？

对于非Angular项目，我正在尝试复制Angular CLI在使用

ng e2e

时所做的操作——不仅要运行量角器，还要首先启动开发服务器，并在完成量角器后完全关闭它

我已经有了一些可以工作的东西，但是我检查webpack dev服务器是否成功启动的方法——查找特定消息“webpack:Compiled successfully.”通过

stdout

——看起来像是一个丑陋的黑客。我通过

pipe

将

stdout

和

stderr

传递到节点进程的方式也不会产生我期望的所有输出

这是我迄今为止的

grandor.conf.js

（还有一堆调试控制台语句，我稍后会清理这些语句）：

---

如有任何改进建议，将不胜感激。我已经找到了一些与这个主题相关的其他线索，但没有得出明确的结论。

由于还没有收到任何其他回复，我想我应该发布一个我以前的代码的清理版本，带有更好的

stderr

输出处理和其他改进，这是迄今为止我得到的最好答案：

const { SpecReporter } = require('jasmine-spec-reporter');
const spawn = require('child_process').spawn;
let webpackServerProcess;
let stderrBuffer = '';

function sendToStderr(s) {
  // Undo console overstriking so that %-progress output appears on separate lines.
  s = s.replace(/ \x08\x08/g, '\x08');
  s = s.replace(/\x08+/g, '\n');
  stderrBuffer += s;

  let eol = stderrBuffer.lastIndexOf('\n');

  if (eol >= 0) {
    process.stderr.write(stderrBuffer.substring(0, eol + 1));
    stderrBuffer = stderrBuffer.substring(eol + 1);
  }
}

function flushStderr() {
  if (stderrBuffer) {
    process.stderr.write(stderrBuffer + '\n');
    stderrBuffer = '';
  }
}

exports.config = {
  allScriptsTimeout: 11000,
  specs: [
    './e2e/**/*.e2e-spec.ts'
  ],
  capabilities: {
    'browserName': 'chrome'
  },
  directConnect: true,
  baseUrl: 'http://localhost:4200/',
  framework: 'jasmine',
  jasmineNodeOpts: {
    showColors: true,
    defaultTimeoutInterval: 30000,
    print: function() {}
  },
  beforeLaunch() {
    return new Promise((resolve, reject) => {
      let resolved = false;
      let rejected = false;

      webpackServerProcess = spawn('webpack-dev-server', ['--port=4200']);
      webpackServerProcess.stdout.pipe(process.stdout);

      webpackServerProcess.stdout.addListener('data', chunk => {
        const msg = chunk.toString();

        if (msg.indexOf('webpack: Compiled successfully.') >= 0) {
          resolved = true;
          flushStderr();
          resolve();
        }
        else if (!resolved && msg.indexOf('webpack:') >= 0) {
          rejected = true;
          flushStderr();
          reject(msg);
        }
      });

      webpackServerProcess.stderr.addListener('data', chunk => {
        sendToStderr(chunk.toString());
      });

      // This config is meant for small projects. Assume that if a minute goes by with no errors, webpack has finished
      // building and webpack-dev-server is ready to go for e2e.
      setTimeout(() => {
        if (!resolved && !rejected) {
          resolved = true;
          resolve();
        }
      }, 60000);

      function done() {
        if (!resolved && !rejected) {
          flushStderr();
          reject('webpack-dev-server terminated unexpectedly');
        }
      }

      webpackServerProcess.addListener('close', done);
      webpackServerProcess.addListener('exit', done);
      webpackServerProcess.addListener('disconnect', done);
    });
  },
  onPrepare() {
    require('ts-node').register({
      project: 'e2e/tsconfig.e2e.json'
    });
    jasmine.getEnv().addReporter(new SpecReporter({ spec: { displayStacktrace: true } }));
  },
  onCleanUp() {
    flushStderr();

    if (webpackServerProcess && !webpackServerProcess.killed) {
      try {
        process.kill(webpackServerProcess.pid);
      }
      catch (error) {}
    }
  }
};

const { SpecReporter } = require('jasmine-spec-reporter');
const spawn = require('child_process').spawn;
let webpackServerProcess;
let stderrBuffer = '';

function sendToStderr(s) {
  // Undo console overstriking so that %-progress output appears on separate lines.
  s = s.replace(/ \x08\x08/g, '\x08');
  s = s.replace(/\x08+/g, '\n');
  stderrBuffer += s;

  let eol = stderrBuffer.lastIndexOf('\n');

  if (eol >= 0) {
    process.stderr.write(stderrBuffer.substring(0, eol + 1));
    stderrBuffer = stderrBuffer.substring(eol + 1);
  }
}

function flushStderr() {
  if (stderrBuffer) {
    process.stderr.write(stderrBuffer + '\n');
    stderrBuffer = '';
  }
}

exports.config = {
  allScriptsTimeout: 11000,
  specs: [
    './e2e/**/*.e2e-spec.ts'
  ],
  capabilities: {
    'browserName': 'chrome'
  },
  directConnect: true,
  baseUrl: 'http://localhost:4200/',
  framework: 'jasmine',
  jasmineNodeOpts: {
    showColors: true,
    defaultTimeoutInterval: 30000,
    print: function() {}
  },
  beforeLaunch() {
    return new Promise((resolve, reject) => {
      let resolved = false;
      let rejected = false;

      webpackServerProcess = spawn('webpack-dev-server', ['--port=4200']);
      webpackServerProcess.stdout.pipe(process.stdout);

      webpackServerProcess.stdout.addListener('data', chunk => {
        const msg = chunk.toString();

        if (msg.indexOf('webpack: Compiled successfully.') >= 0) {
          resolved = true;
          flushStderr();
          resolve();
        }
        else if (!resolved && msg.indexOf('webpack:') >= 0) {
          rejected = true;
          flushStderr();
          reject(msg);
        }
      });

      webpackServerProcess.stderr.addListener('data', chunk => {
        sendToStderr(chunk.toString());
      });

      // This config is meant for small projects. Assume that if a minute goes by with no errors, webpack has finished
      // building and webpack-dev-server is ready to go for e2e.
      setTimeout(() => {
        if (!resolved && !rejected) {
          resolved = true;
          resolve();
        }
      }, 60000);

      function done() {
        if (!resolved && !rejected) {
          flushStderr();
          reject('webpack-dev-server terminated unexpectedly');
        }
      }

      webpackServerProcess.addListener('close', done);
      webpackServerProcess.addListener('exit', done);
      webpackServerProcess.addListener('disconnect', done);
    });
  },
  onPrepare() {
    require('ts-node').register({
      project: 'e2e/tsconfig.e2e.json'
    });
    jasmine.getEnv().addReporter(new SpecReporter({ spec: { displayStacktrace: true } }));
  },
  onCleanUp() {
    flushStderr();

    if (webpackServerProcess && !webpackServerProcess.killed) {
      try {
        process.kill(webpackServerProcess.pid);
      }
      catch (error) {}
    }
  }
};