Populate with TypeScript使用TypeScript填充

#native_company# — #native_desc#

~~Mongoose's TypeScript bindings~~Mongoose的TypeScript绑定 ~~add a generic parameter Paths to the populate():~~将泛型参数Paths添加到populate()中：

import { Schema, model, Document, Types } from 'mongoose';

// `Parent` represents the object as it is stored in MongoDB
interface Parent {
  child?: Types.ObjectId,
  name?: string
}
const ParentModel = model<Parent>('Parent', new Schema({
  child: { type: Schema.Types.ObjectId, ref: 'Child' },
  name: String
}));

interface Child {
  name: string;
}
const childSchema: Schema = new Schema({ name: String });
const ChildModel = model<Child>('Child', childSchema);

// Populate with `Paths` generic `{ child: Child }` to override `child` path
ParentModel.findOne({}).populate<{ child: Child }>('child').orFail().then(doc => {
  // Works
  const t: string = doc.child.name;
});

~~An alternative approach is to define a PopulatedParent interface and use Pick<> to pull the properties you're populating.~~另一种方法是定义一个PopulatedParent接口，并使用Pick<>来提取正在填充的属性。

import { Schema, model, Document, Types } from 'mongoose';

// `Parent` represents the object as it is stored in MongoDB
interface Parent {
  child?: Types.ObjectId,
  name?: string
}
interface Child {
  name: string;
}
interface PopulatedParent {
  child: Child | null;
}
const ParentModel = model<Parent>('Parent', new Schema({
  child: { type: Schema.Types.ObjectId, ref: 'Child' },
  name: String
}));
const childSchema: Schema = new Schema({ name: String });
const ChildModel = model<Child>('Child', childSchema);

// Populate with `Paths` generic `{ child: Child }` to override `child` path
ParentModel.findOne({}).populate<Pick<PopulatedParent, 'child'>>('child').orFail().then(doc => {
  // Works
  const t: string = doc.child.name;
});

Using `PopulatedDoc`使用`PopulatedDoc`

~~Mongoose also exports a PopulatedDoc type that helps you define populated documents in your document interface:~~Mongoose还导出一个PopulatedDoc类型，帮助您在文档界面中定义已填充的文档：

import { Schema, model, Document, PopulatedDoc } from 'mongoose';

// `child` is either an ObjectId or a populated document
interface Parent {
  child?: PopulatedDoc<Document<ObjectId> & Child>,
  name?: string
}
const ParentModel = model<Parent>('Parent', new Schema({
  child: { type: 'ObjectId', ref: 'Child' },
  name: String
}));

interface Child {
  name?: string;
}
const childSchema: Schema = new Schema({ name: String });
const ChildModel = model<Child>('Child', childSchema);

ParentModel.findOne({}).populate('child').orFail().then((doc: Parent) => {
  const child = doc.child;
  if (child == null || child instanceof ObjectId) {
    throw new Error('should be populated');
  } else {
    // Works
    doc.child.name.trim();
  }
});

~~However, we recommend using the .populate<{ child: Child }> syntax from the first section instead of PopulatedDoc. Here's two reasons why:~~但是，我们建议使用第一节中的.populate<{ child: Child }>语法，而不是PopulatedDoc。原因有两个：

~~You still need to add an extra check to check if child instanceof ObjectId.~~ 您仍然需要添加一个额外的检查来检查child instanceof ObjectId。~~Otherwise, the TypeScript compiler will fail with Property name does not exist on type ObjectId.~~ 否则，TypeScript编译器将失败，因为Property name does not exist on type ObjectId。~~So using PopulatedDoc<> means you need an extra check everywhere you use doc.child.~~因此，使用PopulatedDoc<>意味着您需要在任何使用doc.child的地方进行额外检查。
~~In the Parent interface, child is a hydrated document, which makes it slow difficult for Mongoose to infer the type of child when you use lean() or toObject().~~在Parent接口中，child是一个水合文档，这使得Mongoose在使用lean()或toObject()时很难推断出child的类型。

Populate with TypeScript使用TypeScript填充

Using PopulatedDoc使用PopulatedDoc

Using `PopulatedDoc`使用`PopulatedDoc`