从mongodb查询所有元素的函数不会填充数组

Question

so i've written a function that should query everything in the files inventory of my mongodb using mongoose, but instead... doesn't. while each element is in fact being read, files.push() doesn't seem to have any effect on the array, as the array is still empty.

while i know that console.log() is not an effective way to debug, considering express still does not render the contents of the array, it is in fact not being populated.

yes, it is being called as getAllFiles(Image) .

code below:

const Image = module.exports = mongoose.model('files', imageSchema);

function getAllFiles(collection) {
  let files = [];

  collection.find({}, (err, buns) => {    
    buns.forEach((bun) => {
      let fin = bun.path.replace("public/", "");
      files.push(fin);
      console.log(fin);
    });
  });

  console.log(files);
  return files;
}

terminal output (ignore extraneous outputs):

wildflower :: src/bunnydb » node app.js
(node:23296) DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.running on port 3000
[]
uploads/9160d961-3d9b-4dea-a39c-f79b86647408.jpg

Answer 1

was able to fix by adding a callback as it was running asynchronously:

function getAllFiles(collection, cb) {
  let files = [];

  collection.find({}, (err, buns) => {    
    console.log('err: ' + err);
    console.log('buns: ' + buns);
    buns.forEach((bun) => {
      let fin = bun.path.replace("public/", "");
      files.push(fin);
      console.log('data: ' + fin);
    });
    cb(files);
  });

  console.log('arr: ' + files);
  return files;
}

and on invocation the callback argument can be used to do stuff with the files