用react写后端的signUp时出现报错undefined string at bcrypt.hashSync，代码如下，报错在生成password时！

const bcrypt = require('bcryptjs')
const jwt = require('jsonwebtoken')
const db = require('../config/db.config.js')
const User = db.user
const errorHandler = require('../utils/errorHandler')module.exports.register = async function(req, res) {const candidate = await User.findOne({where: {username: req.body.username}})if (candidate) {res.status(409).json({message: 'This login is already taken. Try another.'})} else {const salt = bcrypt.genSaltSync(10)const password = req.body.passwordconst user = new User({name: req.body.name,username: req.body.username,roles: req.body.roles,photoSrc: req.file ? req.file.path: '',password: bcrypt.hashSync(password, salt)})try {await user.save()res.status(201).json(user)} catch(e) {errorHandler(res, e)}}
}

修改方式，在生成salt和password时，使用await，因为本身就是异步运行：

const salt = await bcrypt.genSaltSync(10);
const password = await req.body.password;