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函数内的全局值不变

formidable global-variables express node.js javascript

kjunz · 技术社区 · 7 年前

我正在使用强大解析一个包含文本和上传图像的传入表单。但是,我无法使用表单中解析的值更新这些全局变量(name、description等)。parse()方法。

如果我控制台。将NewCampGrand对象记录在表单中。方法,每个字段值都会正确保存。但只要我一安慰。在parse方法之外记录相同的新Campground对象,该对象为空。我花了2个小时试图解决这个问题,但我无法让它工作。任何帮助都将不胜感激!

  var name;
  var description;
  var price;
  var image;
  var author = {
          id: req.user._id,
          username: req.user.username
  };
  var newCampground = {name: name,
                     image: image,
                     description: description,
                     author: author,
                     price: price,
                     uploadImage: uploadImage
                     } ;

var form = formidable.IncomingForm();
form.parse(req, function(err, fields, files){

   newCampground["name"] = fields.name;
   newCampground.description = fields.description;
   newCampground.price = fields.price;
   newCampground.image = fields.image;
   console.log("Inside of parsed method);
   console.log(JSON.stringify({newCampground}));//this one has everything
});
console.log("Outside of parsed method);
console.log(JSON.stringify({newCampground}));//nothing inside

// ===============console output==================//
Outside of parsed method
{"newCampground":{"author":{"id":"5ab8893a4dd21b478f8d4c40","username":"jun"}}}
Inside of parsed method
{"newCampground":{"name":"aaaaa","image":"","description":"ddddd","author":{"id":"5ab8893a4dd21b478f8d4c40","username":"jun"},"price":"vvvvv","uploadImage":"/uploads/i.jpg"}}
{ author: { id: 5ab8893a4dd21b478f8d4c40, username: 'jun' },
  comments: [],
  _id: 5ac4164432f6902a2178e877,
  __v: 0 }

1 回复 | 直到 7 年前

CertainPerformance 7 年前

form.parse 跑 异步地 -当你 console.log 外面还没有 parse d还没有。要么将所有处理新变量的功能都放在回调函数中,要么将回调函数变成承诺并执行 .then 或者把回访变成承诺 await 承诺的决议。

我擅自修复了可能是无意中出现的语法错误 console.log("Inside of parsed method); 和 console.log("Outside of parsed method); .

async function myFunc() {
  var name;
  var description;
  var price;
  var image;
  var author = {
    id: req.user._id,
    username: req.user.username
  };
  var newCampground = {
    name: name,
    image: image,
    description: description,
    author: author,
    price: price,
    uploadImage: uploadImage
  };

  var form = formidable.IncomingForm();
  await new Promise(resolve => {
    form.parse(req, function(err, fields, files) {
      newCampground["name"] = fields.name;
      newCampground.description = fields.description;
      newCampground.price = fields.price;
      newCampground.image = fields.image;
      console.log("Inside of parsed method");
      console.log(JSON.stringify({
        newCampground
      }));
      resolve();
    });
  });
  console.log("Outside of parsed method");
  console.log(JSON.stringify({
    newCampground
  }));
}
myFunc();