Trying to hash a password using bcrypt inside an async function

问题

Following on from this question.

I feel like I'm almost there, but my incomplete understanding of async is preventing me from solving this. I'm basically trying to just hash a password using bcrypt and have decided to seperate out the hashPassword function so that I can potentially use it in other parts of the app.

hashedPassword keeps returning undefined though...

userSchema.pre('save', async function (next) {

  let user = this
  const password = user.password;

  const hashedPassword = await hashPassword(user);
  user.password = hashedPassword

  next()

})

async function hashPassword (user) {

  const password = user.password
  const saltRounds = 10;

  const hashedPassword = await bcrypt.hash(password, saltRounds, function(err, hash) {

    if (err) {
      return err;
    }

    return hash

  });

  return hashedPassword

}

回答1:

await dosent wait for bcrypt.hash because bcrypt.hash does not return a promise. Use the following method, which wraps bcrypt in a promise in order to use await.

async function hashPassword (user) {

  const password = user.password
  const saltRounds = 10;

  const hashedPassword = await new Promise((resolve, reject) => {
    bcrypt.hash(password, saltRounds, function(err, hash) {
      if (err) reject(err)
      resolve(hash)
    });
  })

  return hashedPassword
}

回答2:

By default, bcrypt.hash(password,10) will return as promise. please check here

Example: Run the code,

var bcrypt= require('bcrypt');

let password = "12345";


var hashPassword = async function(){
    console.log(bcrypt.hash(password,10));
    var hashPwd = await bcrypt.hash(password,10);
    console.log(hashPwd);
}

hashPassword();

Output:

Promise { <pending> }
$2b$10$8Y5Oj329TeEh8weYpJA6EOE39AA/BXVFOEUn1YOFC.sf1chUi4H8i

When you use await inside the async function, it will wait untill it get resolved from the promise.

回答3:

Hashing bcrypt asynchronously should be like this

bcrypt.hash(password, saltRounds, function(err, hash) {
  if (err) {
     throw err;
  }
  // Do whatever you like with the hash
});

If you are confused with sync and async. You need to read more about them. There are a lot of good articles out there.

回答4:

use The method bcrypt.hashSync() for example

const encrypt = async (password) => {
     const hashed = await bcrypt.hashSync(password,saltRounds)
     return hashed
}

来源：https://stackoverflow.com/questions/48799894/trying-to-hash-a-password-using-bcrypt-inside-an-async-function

标签

javascript

node.js

mongoose

bcrypt