使用 async 需要 async 函数，但我的函数是 async [英] Using async requires async function, but my function is async

问题描述

我正在改编一个使用回调的库来使用承诺.当我使用 then() 时它可以工作，但是当我使用 await 时它不起作用.

I'm adapting a library that uses callback to use Promises. It's working when I use then(), but it doesn't work when I use await.

> dbc.solve
[AsyncFunction]
> await dbc.solve(img)
await dbc.solve(img)
^^^^^

SyntaxError: await is only valid in async function

dbc.solve 的代码是:

The code for dbc.solve is:

module.exports = DeathByCaptcha = (function() {
  function DeathByCaptcha(username, password, endpoint) {
    ...
  }

  DeathByCaptcha.prototype.solve = async function(img) {
    return new Promise(
      function(resolve, reject) {
        ...
      }
    );
  };
})();

我相信这与 solve 是 prototype 的成员有关，但我找不到任何关于它的信息.我发现该节点没有始终支持类方法的异步等待，所以我从节点 7，现在我使用节点 9.4.0.

I believe this has something with the fact solve is member of prototype, but I couldn't find any information about it. I found that node didn't always supported async await for class methods, so I upgraded from node 7, now I'm using node 9.4.0.

推荐答案

您没有正确阅读该错误消息:问题不在于您正在调用的函数，而在于您所在的函数强>.

You don't read that error message right: the problem isn't the function you're calling but the function you're in.

你可以这样做

(async function(){
    await dbc.solve(img);
    // more code here or the await is useless
})();

请注意，节点的 REPL 中应该很快不再需要此技巧:https://github.com/nodejs/node/issues/13209

Note that this trick should soon enough not be needed anymore in node's REPL: https://github.com/nodejs/node/issues/13209

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