类型错误：connectToMongo不是函数

• 我的代码（Index.js）*

const connectToMongo = require('./db')
connectToMongo();

• 我的代码（db.js）*

const mongoose = require('mongoose');
const mongoURI = "mongodb://localhost:27017"

const connectToMongo = ()=> {
    mongoose.connect(mongoURI,()=>{
        console.log("Connected to mongo successfully")
    })
}

module.export = connectToMongo;

任何人都可以帮助？