Typegoose和NestJS:类型上不存在属性“保存”

Question

我的后端服务器使用的是类型鹅和nestjs。在我的pages.service.ts文件中已经有了一个函数，可以通过ID获得一个名为getPageById()的页面。当我试图从我的pages.services.ts文件中的另一个调用这个函数时，我通过类型记录得到以下错误：

Property 'save' does not exist on type 'page'

我的page.model.ts文件如下所示

import { DocumentType, modelOptions, prop, Severity } from "@typegoose/typegoose";
import { Content } from "./models/content.model";

@modelOptions({
    schemaOptions: {
        timestamps: true,
        toJSON: {
            transform: (doc: DocumentType<Page>, ret) => {
                delete ret.__v;
                ret.id = ret._id;
                delete ret._id;
            }
        }
    },
    options: {
        allowMixed: Severity.ALLOW
    }
})
export class Page {
    @prop({required: true})
    title: string;

    @prop({required: true})
    description: string;

    @prop({required: true})
    content: Content;

    @prop()
    createdAt?: Date;

    @prop()
    updatedAt?: Date;

    @prop()
    category: string;
}

我的pages.service.ts文件看起来像这样

import { Injectable, NotFoundException } from '@nestjs/common';
import { ReturnModelType } from '@typegoose/typegoose';
import { InjectModel } from 'nestjs-typegoose';
import { createPageDto } from './dto/create-page.dto';
import { Page } from './page.entity';

@Injectable()
export class PagesService {
    constructor(
        @InjectModel(Page)
        private readonly pageModel: ReturnModelType<typeof Page>
    ) {}

    async getPageById(id: string): Promise<Page> {
        let page;
        try {
            page = await this.pageModel.findById(id);
        } catch (error) {
            throw new NotFoundException(`Page could not be found`);
        }
        if (!page) {
            throw new NotFoundException(`Page could not bet found`);
        }
        return page;
    }

    async updatePageCategory(id: string, category: string): Promise<Page> {
        const page = await this.getPageById(id);
        page.category = category;
        page.save() // i get the error here
        return page;
    }
}

我需要什么才能让它发挥作用？

更新

我能修好窃听器。我将返回类型改为Promise<DocumentType<Page>>，如下所示

async getPageById(id: string): Promise<DocumentType<Page>> {
    let page;
    try {
        page = await this.pageModel.findById(id);
    } catch (error) {
        throw new NotFoundException(`Page could not be found`);
    }
    if (!page) {
        throw new NotFoundException(`Page could not bet found`);
    }
    return page;
}

但这是解决这个问题的最好方法吗？

Answer 1

 async updatePageCategory(id: string, category: string): Promise<Page> {
        const page = await this.getPageById(id);
        page.category = category;
        this.pageModel.save(page) // this is the solution
        return page;
    }