在javascript中组合多个回调

Question

在我的chrome.runtime.onMessage.addListener 的回拨响应中未定义或True。当chrome.runtime.onMessage.addListener 收到消息时，它会与本机应用程序通信并检索响应。我想将该响应返回给chrome.runtime.onMessage.addListener 响应。我尝试学习如何组合两个回调，但那里没有任何运气。

async processMsg(response, param2) {}

async function A1(msg, sender) {
      await chrome.runtime.sendNativeMessage(hostName, mesg,async function(response) {
            var resp = await processMsg(response, param2);
            return resp;
        });

  return true;
}


chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
   A1(msg, sender).then(sendResponse);
    return true;
});

Answer 1

你应该在 A1 函数中返回 promise，像这样：

async processMsg(response, param2) {
    return "not null"
}

async function A1(msg, sender) {
    return await chrome.runtime.sendNativeMessage(hostName, mesg,async function(response) {
        return processMsg(response, param2);
    });
}

chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
    A1(msg, sender).then(sendResponse);
    return true; //I don't think you need to return anything here
});