错误：将标头发送到客户端后无法设置标头

Question

我编码Promise.all，它在运行时从db加载大约20行，它停止了

我的代码

router.get('/', (req, res) => {
  var cat = res.locals.lcCategories;

Promise.all([postModel.getTop10View(),postModel.getTop10latest()]).then(data => {
    console.log(data);
    return res.render('home');
  }).catch(next);

});

错误：

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:470:11)
    at ServerResponse.header (C:\Users\tranh\Desktop\Web2-News\node_modules\express\lib\response.js:767:10)
    at ServerResponse.send (C:\Users\tranh\Desktop\Web2-News\node_modules\express\lib\response.js:170:12)
    at done (C:\Users\tranh\Desktop\Web2-News\node_modules\express\lib\response.js:1004:10)
    at Immediate.<anonymous> (C:\Users\tranh\Desktop\Web2-News\node_modules\express-handlebars\lib\utils.js:26:13)
    at runCallback (timers.js:705:18)
    at tryOnImmediate (timers.js:676:5)
    at processImmediate (timers.js:658:5)

Answer 1

我有同样的问题，当您的api已经发送响应时，基本上会发生此错误，但是由于nodejs的异步能力或丢失的周期，它再次发送了响应，我认为promise.all已运行并且请求仍然存在发送，并且当promise.all从其循环返回时，它再次发送一个请求。 在promise.all之前使用await 像

await Promise.all([postModel.getTop10View(),postModel.getTop10latest()]).then(data => {
        console.log(data);
        return res.render('home');
      }).catch(next);