javascript - 通过 receiveMessage 恢复等待异步脚本

Question

Client1 在窗口内有一个 iframe。Client2 通过异步脚本向 Client1 发送 postMessage()，然后 Client1 执行某些操作(绕过跨域策略限制)。到目前为止，它运行得很好。现在，Client1 应该将 postMessage() 返回给 Client2，以便他 (2) 可以结束等待(因为 async.script 执行)。

如何实现。

代码片段:

客户端 2

var iframe;
    return browser.executeAsyncScript(function (done) {
        window.addEventListener("message", receiveMessage);
        iframe = document.getElementById("myIframe");
        iframe.contentWindow.postMessage("message", "*");
        ##### HERE COMES HOW TO END WAITING #####
    }).then(function () {

    });

客户端 1

script.function setup() {
            window.addEventListener("message", receiveMessage);
        }

script.function receiveMessage(event) {
            if (event.data !== "message")
                return;
            // done something
            event.source.postMessage("message", event.origin); ?????
            // sth. like this
        }

非常感谢您的任何提示

Answer 1

不确定 Client2 中的 receiveMessage 是什么，但由于 addEventListener 将执行所有匹配的处理程序，我只需添加另一个事件，如果 receiveMessage与 Client1 中的不同，并且 done 可以通过 receiveMessage` 访问，那么您不需要我刚刚创建的新事件处理程序。

var iframe;

// The done passed in is the function to decide when to end the waiting.
// When you call `done`, the promise return by `browser.executeAsyncScript` knows its resolved
// and it'll start to execute whats in the `.then`.
return browser.executeAsyncScript(function (done) {
  // Dunno what `receiveMessage` is, or whether `done` is accessible to it, 
  //so I just created another function.
  // If its separate from one in `Client1`, than put the codes in `endWaitHandler` here.
  window.addEventListener("message", receiveMessage);

  var endWaitHandler = function() {
    // When we receive the message, call done to resolve promise
    done();

    // Remove the endWaitHandler so it won't get register many times if
    // this function called multiple times.
    window.removeEventListener("message", endWaitHandler);
  };

  // Register before sending the message.
  window.addEventListener("message", endWaitHandler);

  iframe = document.getElementById("myIframe");
  iframe.contentWindow.postMessage("message", "*");
}).then(function () {

});