Node.js async.each引发“回调已被调用”

-1

此问题可能看起来像许多其他人的副本，但我无法在任何地方找到我的错误。Node.js async.each引发“回调已被调用”

问题是，async.each引发“回调已被调用”。这里的片段（我称为异步回调done，所以它不会在我的代码的其它回调感到困惑）：

async.each(this.requirements, (requirement, done) => { 
    // That thing here passes the result as a callback 
    requirement.callback((result) => { 
    if (!result) { 
     // requirement not passed -> return error 
     done(true); // LINE 42 
    } else { 
     done(); // LINE 44 
    } 
    }, data, params, bot); 
}, (err) => { // 'done' callback 
    log.info('handler', 
    `Handler '${this.label}' ${err ? 'failed' : 'succeeded'}`); 
    // if any requirement did not pass, do not execute handler callback 
    if (!err) this.callback(data, params, bot); 
});

这里是它的堆栈跟踪：

C:\Users\samuel\Code\node\sk22tgjs\node_modules\async\dist\async.js:837 
      if (fn === null) throw new Error("Callback was already called."); 
         ^

Error: Callback was already called. 
    at C:\Users\samuel\Code\node\sk22tgjs\node_modules\async\dist\async.js:837:34 
    at requirement.callback (C:\Users\samuel\Code\node\sk22tgjs\node_modules\telegramjs\core\handler.js:44:11) 
    at Requirement.exports.command.Requirement.callback (C:\Users\samuel\Code\node\sk22tgjs\node_modules\telegramjs\telegram\requires.js:21:5) 
    at async.each (C:\Users\samuel\Code\node\sk22tgjs\node_modules\telegramjs\core\handler.js:39:19) 
    at C:\Users\samuel\Code\node\sk22tgjs\node_modules\async\dist\async.js:2953:18 
    at replenish (C:\Users\samuel\Code\node\sk22tgjs\node_modules\async\dist\async.js:872:19) 
    at C:\Users\samuel\Code\node\sk22tgjs\node_modules\async\dist\async.js:878:27 
    at C:\Users\samuel\Code\node\sk22tgjs\node_modules\async\dist\async.js:840:18 
    at requirement.callback (C:\Users\samuel\Code\node\sk22tgjs\node_modules\telegramjs\core\handler.js:44:11) 
    at Requirement.callback (C:\Users\samuel\Code\node\sk22tgjs\node_modules\telegramjs\core\requires.js:19:5)

有趣事情是，只有done(true)被调用才会发生问题。然而，在第44行出现错误，而不是42

您还可以看到在GitHub上腐败的代码，尤其是testing分支：https://github.com/22sk/telegramjs

在此先感谢。

来源

2016-07-19 22samuelk

https://github.com/22sk/telegramjs/blob/master/telegram/requires.js#L16缺少return语句，以防止从'获取调用两次result'？（为什么堆栈跟踪指向21行） –

啊，该死的。没有想到那么远，谢谢。你会把它作为答案吗？ – 22samuelk

为了清楚起见，摆脱了箭头功能 –

如果找不到命令，则会调用成功和失败，而不仅仅是失败。

https://github.com/22sk/telegramjs/blob/5b85f04fe890a8fd32b373edb97bfebc923156b1/bot/telegram/requires.js

exports.command = new Requirement({ 
    label: 'command', 
    requires: requires.has('message', 'text'), 
    callback: (result, data, params, bot) => { 
    const command = new Command(data.message.text); 
    if (!command.valid || command.bot && bot.me.username !== command.bot) { 
     // command is not valid or not meant to be handled by this bot 
     result(false); // <--- ### Missing return ### ---> 
    } 
    // command is valid and should be handled by this bot 
    // write command into data 
    params.command = command; 
    result(true); 
    } 
});

来源

2016-07-19 17:53:55

Node.js async.each引发“回调已被调用”

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