Constructs explanation

[ssow]

Greetings,

Would you mind explain/comment the following construct, which I'm not familiar with :

public async SignUp(userInputDTO: IUserInputDTO): Promise<{ user: IUser; token: string }>

export default ({ mongoConnection, models }: { mongoConnection; models: { name: string; model: any }[] })

export default mongoose.model<IUser & mongoose.Document>('User', User);

Do they require a special package ? Where can I find a documentation ?
Thank you

[santiq]

Sure.
This project is written in typescript, so

public async SignUp(userInputDTO: IUserInputDTO): Promise<{ user: IUser; token: string }> {
...
}

There we are using typescript to type the response of the function, which will be Promise where it holds a value that is an object with the shape of { user, token }

In plain javascript would be something similar to this

async SignUp(userInputDTO) {
 ...
};

======

Here we are using Mongoose, which is a node.js package to connect to Mongodb and an ODM

export default mongoose.model<IUser & mongoose.Document>('User', User);

The part where we are using <> is called Generics it is used to give a Type to the result of the database's results.

Then the IUser & mongoose.Document is telling that the results of the databases will be an object which type is the Intersection of the interface IUser and the interface mongoose.Document

In practice, the mongoose.Document means that the result will have the property _id and all of the properties of the interface IUser

======

This is a little trickier

 export default ({ mongoConnection, models }: { mongoConnection; models: { name: string; model: any }[] })

We are exporting an object, which has this shape: { mongoConnection, models }
but also defining the type on the same line with the : operator.
since models is an array of objects, I'm saying that each object of the array will have the shape { name: string, model: any}

[ssow]

Very kind of you and cristal clear.
May i ask you a last explanation regarding the following type declaration and the purpose of the Models namespace please ?

namespace Models {
export type UserModel = Model<IUser & Document>;
}

Thank you.