夜视：有没有办法确定executeAsync是否执行了javascript？

我在用夜视来写浏览器自动化。我对Nightwatch命令的executeAsync函数有问题

executeAsync的夜间监视文档：

将JavaScript片段插入页面，以便在 当前选定帧的上下文。执行的脚本是 假设是异步的，对脚本求值的结果是 返回给客户

异步脚本命令不能跨越页面加载。如果卸货 事件在等待脚本结果时被激发，应显示错误 返回给客户

异步任务完成时，将调用最后一个应为函数的可选参数

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如何检查异步任务是否已开始执行？我想在浏览器执行异步任务的Javascript主体后立即执行一些操作。有没有办法确定executeAsync是否已开始在夜间监视代码中执行？

调用保持同步，其行为类似于执行流中的执行。 要异步执行某些代码，首先需要使用

execute

启动脚本，然后使用

executeAsync

等待结果

以下是一个例子：

'Demo asynchronous script' : function (client) {
  client.timeoutsAsyncScript(10000);
  client.url('http://stackoverflow.com/');

  // execute a piece of script asynchroniously
  client.execute(function(data) {
        window._asyncResult = undefined;
        setTimeout(function(){
          window._asyncResult = "abcde";
        }, 2000);
     }, ["1234"]);

   // execute a task while the asynchroniously script is running
   client.assert.title('Stack Overflow');

   // wait for the asynchronous script to set a result
   client.executeAsync(function(done) {
        (function fn(){
            if(window._asyncResult !== undefined)
              return done(window._asyncResult);
            setTimeout(fn, 30);
        })();
   }, [], function(result) {
     // evaluate the result
     client.assert.equal(result.value, "abcde");
   });

  client.end();
}

'Demo asynchronous script' : function (client) {
  client.timeoutsAsyncScript(10000);
  client.url('http://stackoverflow.com/');

  // execute a piece of script asynchroniously
  client.execute(function(data) {
        window._asyncResult = undefined;
        setTimeout(function(){
          window._asyncResult = "abcde";
        }, 2000);
     }, ["1234"]);

   // execute a task while the asynchroniously script is running
   client.assert.title('Stack Overflow');

   // wait for the asynchronous script to set a result
   client.executeAsync(function(done) {
        (function fn(){
            if(window._asyncResult !== undefined)
              return done(window._asyncResult);
            setTimeout(fn, 30);
        })();
   }, [], function(result) {
     // evaluate the result
     client.assert.equal(result.value, "abcde");
   });

  client.end();
}