Mongoose ODM

// npm install mongoose
const mongoose = require("mongoose");

// Connect to MongoDB
mongoose.connect("mongodb://localhost:27017/myapp")
  .then(() => console.log("MongoDB connected!"))
  .catch(err => console.error("Connection error:", err));

// Schema define karo
const userSchema = new mongoose.Schema({
  name: {
    type: String,
    required: [true, "Name required hai"],
    trim: true,
    minlength: [2, "Name kam se kam 2 characters ka hona chahiye"]
  },
  email: {
    type: String,
    required: true,
    unique: true,
    lowercase: true,
    match: [/^[^s@]+@[^s@]+.[^s@]+$/, "Valid email chahiye"]
  },
  age: {
    type: Number,
    min: [0, "Age negative nahi ho sakta"],
    max: 150
  },
  role: {
    type: String,
    enum: ["user", "admin", "moderator"],
    default: "user"
  },
  isActive: { type: Boolean, default: true },
  createdAt: { type: Date, default: Date.now }
}, {
  timestamps: true // createdAt aur updatedAt auto add
});

// Method add karo
userSchema.methods.getDisplayName = function() {
  return `${this.name} (${this.role})`;
};

const User = mongoose.model("User", userSchema);
module.exports = User;

const User = require("./user-model");

// CREATE
async function createUser(data) {
  const user = new User(data);
  return await user.save();
  // OR: return await User.create(data);
}

// READ
async function getUsers() {
  return await User
    .find({ isActive: true })
    .select("name email role") // sirf yeh fields
    .sort({ createdAt: -1 })  // newest first
    .limit(10);
}

async function findByEmail(email) {
  return await User.findOne({ email });
}

// UPDATE
async function updateUser(id, updates) {
  return await User.findByIdAndUpdate(
    id,
    { $set: updates },
    { new: true, runValidators: true } // updated doc return karo
  );
}

// DELETE
async function deleteUser(id) {
  return await User.findByIdAndDelete(id);
}