How to save an array of strings using mongoose schema

I have this schema to represent a user:

const UserSchema = mongoose.Schema({
    username: {
        type: String,
        required: false
    },
    social: [{
        facebook: {
            type: String,
            required: false
        },
        twitter: {
            type: String,
            required: false
        }
    }]
});

how can I save values using this schema? What I am doing so far:

user.username = username;
user.social['facebook'] = facebook;
user.social['twitter'] = twitter;

await user.save();

this works for username but social is still an empty array. I also tried

user.social.facebook = facebook;
user.social.twitter = twitter;

same result:

 "social" : [ ]

>Solution :

Are you sure that you really want social field to be an array? Since it stores facebook and twitter accounts, it is logical that each user will have only one of these accounts. In that case, it is better if you define social to be object with nested properties. That is easier to maintain and it will work with your code.

social: {
  facebook: { type: String, required: false },
  twitter: { type: String, required: false }
}

If you really need social field to be an array, you can change your code like this:

user.username = username;
user.social[0] = {
  'facebook': facebook,
  'twitter': twitter,
};

await user.save();