如何使用 model.find()、Mongoose 中的 var

Question

I want to use var bot_man how can I pass to out of function.

var bot_man = ''
  Post.find({ title: 'bot_status' }, function (err, author) {
    if (err) throw err
    bot_man = author[0].body
    console.log(author[0].body) //output => 'on'
  })
  console.log(`result = ${bot_man}`) // result = 

result is '' result =

Answer 1

Post.find is an asynchronous function. When you call it it with a callback it defers callback's execution untill the result is ready (somewhere in the future) and immediatelly proceeds to the next line. Thus bot_man is still an empty string when evaluated in console.log('result = ${bot_man}') .

To get the result you'd better off making your function async and rewrite it as:

let author = await Post.find({ title: 'bot_status' }).exec()
let bot_man = author[0].body

console.log(`result = ${bot_man}`)

Though for production code it still lacks some sanity checks. Whether author is not null or empty and error handling. I didn't include them into the snippet to not complicate the code.