I have been looking into NestJS recently and started some sample project. This project uses MongoDB, so I also chose Typegoose to make this happen. I found a tutorial online (https://nartc.netlify.app/blogs/nestjs-typegoose/) that describes how to use some abstractions with base typegoose models.
So, my base.service.ts now looks like this:
import { InternalServerErrorException } from '@nestjs/common';
import { DocumentType, ReturnModelType } from '@typegoose/typegoose';
import { AnyParamConstructor } from '@typegoose/typegoose/lib/types';
import { MongoError } from 'mongodb';
import { DocumentQuery, Types, Query, UpdateQuery } from 'mongoose';
import { BaseModel } from './base.model';
type QueryList<T extends BaseModel> = DocumentQuery<
Array<DocumentType<T>>,
DocumentType<T>
>;
type QueryItem<T extends BaseModel> = DocumentQuery<
DocumentType<T>,
DocumentType<T>
>;
export abstract class BaseService<T extends BaseModel> {
protected model: ReturnModelType<AnyParamConstructor<T>>;
protected constructor(model: ReturnModelType<AnyParamConstructor<T>>) {
this.model = model;
}
protected static throwMongoError(err: MongoError): void {
throw new InternalServerErrorException(err, err.errmsg);
}
protected static toObjectId(id: string): Types.ObjectId {
try {
return Types.ObjectId(id);
} catch (e) {
this.throwMongoError(e);
}
}
createModel(doc?: Partial<T>): T {
return new this.model(doc);
}
findAll(filter = {}): QueryList<T> {
return this.model.find(filter);
}
async findAllAsync(filter = {}): Promise<Array<DocumentType<T>>> {
try {
return await this.findAll(filter).exec();
} catch (e) {
BaseService.throwMongoError(e);
}
}
findOne(filter = {}): QueryItem<T> {
return this.model.findOne(filter);
}
async findOneAsync(filter = {}): Promise<DocumentType<T>> {
try {
return await this.findOne(filter).exec();
} catch (e) {
BaseService.throwMongoError(e);
}
}
findById(id: string): QueryItem<T> {
return this.model.findById(BaseService.toObjectId(id));
}
async findByIdAsync(id: string): Promise<DocumentType<T>> {
try {
return await this.findById(id).exec();
} catch (e) {
BaseService.throwMongoError(e);
}
}
async create(item: T): Promise<DocumentType<T>> {
try {
return await this.model.create(item);
} catch (e) {
BaseService.throwMongoError(e);
}
}
delete(filter = {}): QueryItem<T> {
return this.model.findOneAndDelete(filter);
}
async deleteAsync(filter = {}): Promise<DocumentType<T>> {
try {
return await this.delete(filter).exec();
} catch (e) {
BaseService.throwMongoError(e);
}
}
deleteById(id: string): QueryItem<T> {
return this.model.findByIdAndDelete(BaseService.toObjectId(id));
}
async deleteByIdAsync(id: string): Promise<DocumentType<T>> {
try {
return await this.deleteById(id).exec();
} catch (e) {
BaseService.throwMongoError(e);
}
}
update(item: T): QueryItem<T> {
return this.model.findByIdAndUpdate(BaseService.toObjectId(item.id), item, {
new: true
});
}
async updateAsync(item: T): Promise<DocumentType<T>> {
try {
return await this.update(item).exec();
} catch (e) {
BaseService.throwMongoError(e);
}
}
count(filter = {}): Query<number> {
return this.model.count(filter);
}
async countAsync(filter = {}): Promise<number> {
try {
return await this.count(filter);
} catch (e) {
BaseService.throwMongoError(e);
}
}
}
This is exact same code from the blog post mentioned above. However, I am getting some errors:
No overload matches this call.
The last overload gave the following error.
Argument of type 'T' is not assignable to parameter of type 'UpdateQuery<DocumentType<T>>'.
Type 'BaseModel' is not assignable to type 'UpdateQuery<DocumentType<T>>'.
Type 'BaseModel' is not assignable to type '_UpdateQuery<_AllowStringsForIds<LeanDocument<DocumentType<T>>>> & ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>> & DotAndArrayNotation<...>'.
Type 'BaseModel' is not assignable to type 'ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>>'.
Type 'T' is not assignable to type '_UpdateQuery<_AllowStringsForIds<LeanDocument<DocumentType<T>>>> & ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>> & DotAndArrayNotation<...>'.
Type 'BaseModel' is not assignable to type '_UpdateQuery<_AllowStringsForIds<LeanDocument<DocumentType<T>>>> & ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>> & DotAndArrayNotation<...>'.
Type 'BaseModel' is not assignable to type 'ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>>'.
Type 'T' is not assignable to type 'ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>>'.
Type 'BaseModel' is not assignable to type 'ReadonlyPartial<_AllowStringsForIds<LeanDocument<DocumentType<T>>>>'.
This error points to update method, into item parameter inside this.model.findByIdAndUpdate(BaseService.toObjectId(item.id), item, ...); I understand that the type of item is <T extends BaseModel> and it works on the blog post, but why do I get an error over here?
Also, this error is also present:
Generic type 'Query<ResultType, DocType, THelpers>' requires between 2 and 3 type arguments.
on count method, in the Query<number>.
The one thing I do not get is why do these errors appear on my project, but not on the tutorial mentioned before?
