Potential Null Object in Typescript Mongoose: A Concern

Encountering an issue while attempting to locate my user model: Object is possibly 'null'. I would like to find a solution that does not involve suppressing TypeScript's strict rule.

const { email, password } = req.body;
const user = await User.findOne({ email:email });
if (!user) {
}
/// This line causes the error
const passwordMatch = await bcrypt.compare(password, user.password);

////User Interface

import { Document } from 'mongoose';
interface User extends Document {
  email: string;
  password: string;
  username: string;
}
export default User;


////User Schema

import mongoose, { Document, Schema, Model, model } from 'mongoose';
import User from '../interfaces/User';

const UserSchema: Schema = new Schema({
  email: { type: String, required: true, unique: true },
  password: { type: String, required: true },
  username: { type: String, required: true },
});
export default mongoose.model<User>('User', UserSchema);

Answer №1

The issue lies in your if statement if (!user) not accounting for null or undefined user values.

To address this, you can add a return statement within the if block to handle null or undefined users:

if (!user) {
  return
}

TypeScript is smart enough to recognize that by the time you reach the passwordMatch line, the user will no longer be null.

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