How to perform user-input validation using if statements

I’m trying to perform user validation using if statements but on testing using post man, I keep on getting only the first return statement ‘Email is required ‘ even after adding a valid email address and also an invalid email address. I have attached the user model, user controller logic and a picture of postman’s response

user schema model

const mongoose = require('mongoose');
const { Schema } = mongoose

const userSchema = new Schema({
    firstName: {
        type: String,
        required: true,
        min: 3,
        max: 20
    },
    lastName: {
        type: String,
        required: true,
        min: 3,
        max: 20
    },
    email: {
        type: String,
        required: true,
        unique: true,
    },
    phoneNumber: {
        type: String,
        required: true,
    },
    password: {
        type: String,
        required: true,
        min: 5
    },
    confirmPassword: {
        type: String,
        required: true,
        min: 5
    }
});

const User = mongoose.model('User', userSchema);

module.exports = User;

user.controller.js

module.exports.users = async(req, res) => {
    try {
        const email = await user.findOne({ email: req.body.email });
        const firstName = await user.find({ firstName: req.body.firstName });
        const lastName = await user.find({ lastName: req.body.lastName });
        const password = await user.find({ password: req.body.password });
        const confirmPassword = await user.find({ confirmPassword: req.body.confirmPassword });
        const phoneNumber = await user.find({ phoneNumber: req.body.phoneNumber });

        if (!email) return res.send('Email is required')

        const filterEmail = /^([a-zA-Z0-9_.-])+@(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/;
        if (!filterEmail.test(email.value)) return
        res.send('Please provide a valid email address');
        if (email) return res.send('Email already exists');

        if (!firstName) return res.send('First Name is required');
        if (firstName.length < 3 || firstName.length > 20) return
        res.send('First name must be at least 3 characters and less than 20 characters');;

        if (!lastName) return res.send('Last Name is required');
        if (lastName.length < 3 || lastName.length > 20) return
        res.send('Last name must be at least 3 characters and less than 20 characters')

        if (!password) return res.send('PassWord is required');
        const filterPassword = /^(?=.*d)(?=.*[a-z])(?=.*[A-Z])(?=.*[^a-zA-Z0-9])(?!.*s).{5,15}$/;
        if (!filterPassword.test(password.value)) return
        res.send('Password must include at least one lowercase letter, one uppercase letter, one digit, and one special character');
        if (!confirmPassword) return res.send(' Please confirm password');
        if (password.value !== confirmPassword.value) return res.send('Passwords do not match');

        if (!phoneNumber) return res.send('Phone Number is required');
        phone(phoneNumber.value);

        let User = new user(_.pick(req.body, ['firstName', 'lastName', 'email', 'phoneNumber', 'password']));

        bcrypt.genSalt(10, async(err, salt) => {
            if (err) throw err;
            return user.password = await bcrypt.hash(user.password, salt);
        });
        await User.save();


    } catch (err) {
        res.status(500).send('Something went wrong');
        console.warn(err);
    }
}

Answer

Your controller is not good. You need to get the email, lastName and firstName from req.body.

   const {email, lastName} = req.body

And then do the validation, which by the way will already happen in mongoose.

    const email = await user.findOne({ email: req.body.email });

In this line you are looking in your DB for a user with email = req.body.email. But since there is no such a user it return your if statement

   if (!email) return res.send('Email is required')

to get your user you only need to compare with one value if you set it to be unique in your schema, for instead user email.

const user = await user.findOne({ email });

In this case email was already destructed and if there is no user, you can create one.

you can use await user.create() and pass your values and hash the password with pre(“save”) in your schema.

    UserSchema.pre("save", async function () {
  if (!this.isModified("password")) return;
  const salt = await bcrypt.genSalt(10);
  this.password = await bcrypt.hash(this.password, salt);
});

You can also validate user email in the schema

        email: {
      type: String,
      required: [true, "Please provide email"],
      match: [
        /^(([^<>()[]\.,;:s@"]+(.[^<>()[]\.,;:s@"]+)*)|(".+"))@(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+[a-zA-Z]{2,}))$/,
        "Please provide a valid email",
      ],
      unique: true,
    },