Type 'Document<any>' is not assignable to type 'Pick<Pick<_LeanDocument<TicketDoc>

Question

I have an error that is clear as mud on my terminal:

TSError: ⨯ Unable to compile TypeScript: [orders-depl-9fbcb84ff-ngt2z orders] src/models/ticket.ts(47,5): error TS2322: Type 'Document' is not assignable to type 'Pick<Pick<_LeanDocument, "_id" | "__v" | "id" | "title" | "price" | "isReserved">, "_id" | "__v" | "id" | "title" | "price"> | QuerySelector<...> | undefined'. [orders-depl-9fbcb84ff-ngt2z orders] Type 'Document' is missing the following properties from type 'Pick<Pick<_LeanDocument, "_id" | "__v" | "id" | "title" | "price" | "isReserved">, "_id" | "__v" | "id" | "title" | "price">': title, price

It's referencing this model file:

import mongoose from 'mongoose';
import { Order, OrderStatus } from './order';

interface TicketAttrs {
  title: string;
  price: number;
}

export interface TicketDoc extends mongoose.Document {
  title: string;
  price: number;
  isReserved(): Promise<boolean>;
}

interface TicketModel extends mongoose.Model<TicketDoc> {
  build(attrs: TicketAttrs): TicketDoc;
}

const ticketSchema = new mongoose.Schema({
  title: {
    type: String,
    required: true
  },
  price: {
    type: Number,
    required: true,
    min: 0
  }
}, {
  toJSON: {
    transform(doc, ret) {
      ret.id = ret._id;
      delete ret._id;
    }
  }
});

ticketSchema.statics.build = (attrs: TicketAttrs) => {
  return new Ticket(attrs);
};
// Run query to look at all orders. Find an order where the 
// ticket is the ticket just found *and* the order status is *not* cancelled.
// If we find an order from that means the ticket *is* reserved
ticketSchema.methods.isReserved = async function () {
  // this === the ticket document that I just called 'isReserved' on
  const existingOrder = await Order.findOne({
    ticket: this,
    status: {
      $in: [
        OrderStatus.Created,
        OrderStatus.AwaitingPayment,
        OrderStatus.Complete
      ]
    }
  });

  return !!existingOrder;
};

const Ticket = mongoose.model<TicketDoc, TicketModel>('Ticket', ticketSchema);

export { Ticket };

I don't see where I have made a syntax error anywhere and I have no idea what this type of Pick is. It seems like the issue is that ticket is not ticket but should be equal to this, except it's not.

renanrider renanrider · Accepted Answer · 2021-04-29T22:54:39

I know it's been a long time. But, I saw this answer in user Jonathan's Udemy questions and answers and I think it's better than disabling TS verification:

Not a big fan of ts-ignore because of reasons stated by Korey above.

I suspect the cause of the problem is the extra isReserved() method added to a Ticket document.

Hence, instead of searching by the Ticket document (this), I searched via the id of the Ticket document (this.id). This should work fine.

ticketSchema.methods.isReserved = async function() {
  const existingOrder = await Order.findOne({
    ticket: this.id, // Ticket id
    status: {
      $in: [
        OrderStatus.Created,
        OrderStatus.AwaitingPayment,
        OrderStatus.Complete
      ]
    }
  })
  return !!existingOrder
}

Type 'Document<any>' is not assignable to type 'Pick<Pick<_LeanDocument<TicketDoc>

2 Answers