how to make a variable a unique key in mongoose?

Question

For example if I have this schema

var userSchema = mongoose.Schema({
    username: String,
    email: String,
    password         


        

Answer 1

You can add a constraint with the unique attribute. This will also add a "unique" index for the field to your collection:

var userSchema = mongoose.Schema({
    username: { type: String, unique: true },
    email: String,
    password: String,
    _todo: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Todo'}]
});