TypeScript docs: query helpers, statics

[UncleVic]

Hi there,

I've tried migrate to v.12 and have some questions.

How can I type populate?
May be I don't understand, but I couldn't set type in Model for populate query.

Can I have strong types for static methods?
Now I can see that any static method has type (...args: any[])

How can I use TQueryHelpers?

Thanks

[vkarpov15]

@UncleVic :

1. Can you please clarify what you mean by "type populate" and "set type in Model for populate query"?

2. No, I think we'll need to add another generic parameter to the Model interface for this.

3. Here's an example in our tests. We don't currently have very good docs for TypeScript.

[vkarpov15]

I took a closer look and for (2) we don't need another generic parameter. Just define a new interface that extends Model and includes the statics you want:

interface IProject extends Document {
  name: string;
}

interface ProjectModel extends Model<IProject> {
  myStatic(n: number): number;
}

const Project = connection.model<IProject, ProjectModel, {}>('Project', projectSchema);
// `Project` gets `myStatic()` from `ProjectModel`
Project.myStatic(42);

[UncleVic]

I have a type:

interface IProject {
  users: Schema.Types.ObjectId[] | IUser[];
}

interface IProjectDocument extends IProject, Document {
  users: IUser[]; 
}

interface IProjectPopulatedDocument extends IProject, Document {
  users: Schema.Types.ObjectId[]; 
}

With a usual query, I have ObjectIds array in field users
When I do populate I should have array of IUser.
For example,

const project =  Project.findById('id'); // project: IProjectDocument
await project.populate('users);  // project: IProjectPopulatedDocument

[jacobmolby]

The way I've solved it is to always populate through a function, then you can cast the the return type to the correct types.
I have for the different scenarios I want to populate as an example.

/**
 *  Takes a listing query, executes it and populates the listing
 * @param listingQuery a mongoose listing query
 */
export const populateListings = async (
  listingQuery: Query<IListing[], IListing>
): Promise<IListing_populated[]> => {
  return (await listingQuery.populate({
    path: 'bids.user owner comments.user comments.answers.user',
    select: 'fullName profilePicture',
  })) as IListing_populated[];
};


/**
 *  Takes a listing query, executes it and populates the listing
 * @param listingQuery a mongoose listing query
 */
export const populateListing = async (
  listingQuery: Query<IListing | null, IListing>
): Promise<IListing_populated | null> => {
  return (await listingQuery.populate({
    path: 'bids.user owner comments.user comments.answers.user',
    select: 'fullName profilePicture',
  })) as IListing_populated;
};


export const populateListingDocument = async (
  listing: IListing
): Promise<IListing_populated> => {
  return (await listing
    .populate({
      path: 'bids.user owner comments.user comments.answers.user',
      select: 'fullName profilePicture',
    })
    .execPopulate()) as IListing_populated;
};

Then it can be consumed like this:

const listing = await populateListing(Listing.findById(listingId));

Where listing is now of type IListing_populated

It can probably be done smarter, but at least this solves it for now