javascript - NodeJS 变量未定义

Question

这个问题已经有答案了:

Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference (7 个回答)

How do I return the response from an asynchronous call? (42 个回答)

已关闭 4 年前。

我似乎找不到为什么这不起作用的问题。当我转到 localhost:3000 时，出现此错误 ReferenceError: pixwords is not defined

app.get('/', (req, res) => {
Word.find().then((pixwords) => {
    if(!pixwords) {
     return res.send('No text available');
    }
});
res.render('index.hbs', {pixwords});
});

这是index.hbs:

{{#each pixwords}}
    {{this.text}}
{{/each}}

Answer 1

pixwords仅在Word.find().then()的回调函数中定义，您只能在那里使用它:

app.get('/', (req, res) => {
  Word.find().then((pixwords) => { // <-- this declares pixwords
    if (!pixwords) {
      return res.send('No text available');
    }
    res.render('index.hbs', { // <-- move the call in the .then
      pixwords
    });
  });
  // anything here is executed before Word.find has finished running
});