Please vote on your prefered method of querying! Take+Skip vs Limit+Offset
Pagination helper method for TypeORM repositories or queryBuilders with strict typings
$ yarn add nestjs-typeorm-paginateor
$ npm i nestjs-typeorm-paginateimport { Injectable } from '@nestjs/common';
import { Repository } from 'typeorm';
import { InjectRepository } from '@nestjs/typeorm';
import { CatEntity } from './entities';
import {
paginate,
Pagination,
IPaginationOptions,
} from 'nestjs-typeorm-paginate';
@Injectable()
export class CatService {
constructor(
@InjectRepository(CatEntity)
private readonly repository: Repository<CatEntity>,
) {}
async paginate(options: IPaginationOptions): Promise<Pagination<CatEntity>> {
return paginate<CatEntity>(this.repository, options);
}
}import { Injectable } from '@nestjs/common';
import { Repository } from 'typeorm';
import { InjectRepository } from '@nestjs/typeorm';
import { CatEntity } from './entities';
import {
paginate,
Pagination,
IPaginationOptions,
} from 'nestjs-typeorm-paginate';
@Injectable()
export class CatService {
constructor(
@InjectRepository(CatEntity)
private readonly repository: Repository<CatEntity>,
) {}
async paginate(options: IPaginationOptions): Promise<Pagination<CatEntity>> {
const queryBuilder = this.repository.createQueryBuilder('c');
queryBuilder.orderBy('c.name', 'DESC'); // Or whatever you need to do
return paginate<CatEntity>(queryBuilder, options);
}
}import { Controller, DefaultValuePipe, Get, ParseIntPipe, Query } from '@nestjs/common';
import { CatService } from './cat.service';
import { CatEntity } from './cat.entity';
import { Pagination } from 'nestjs-typeorm-paginate';
@Controller('cats')
export class CatsController {
constructor(private readonly catService: CatService) {}
@Get('')
async index(
@Query('page', new DefaultValuePipe(1), ParseIntPipe) page: number = 1,
@Query('limit', new DefaultValuePipe(10), ParseIntPipe) limit: number = 10,
): Promise<Pagination<CatEntity>> {
limit = limit > 100 ? 100 : limit;
return this.catService.paginate({
page,
limit,
route: 'http://cats.com/cats',
});
}
}If you use
ParseIntPipeon the query params (as in the example), don't forget to also addDefaultValuePipe. See issue 517 for more info.
the
routeproperty of the paginate options can also be the short version of an absolute path , In this case, it would be/catsinstead ofhttp://cats.com/cats
{
"items": [
{
"lives": 9,
"type": "tabby",
"name": "Bobby"
},
{
"lives": 2,
"type": "Ginger",
"name": "Garfield"
},
{
"lives": 6,
"type": "Black",
"name": "Witch's mate"
},
{
"lives": 7,
"type": "Purssian Grey",
"name": "Alisdaya"
},
{
"lives": 1,
"type": "Alistair",
"name": "ali"
},
...
],
"meta": {
"itemCount": 10,
"totalItems": 20,
"itemsPerPage": 10,
"totalPages": 5,
"currentPage": 2
},
"links" : {
"first": "http://cats.com/cats?limit=10",
"previous": "http://cats.com/cats?page=1&limit=10",
"next": "http://cats.com/cats?page=3&limit=10",
"last": "http://cats.com/cats?page=5&limit=10"
}
}items: An array of SomeEntity
meta.itemCount: The length of items array (i.e., the amount of items on this page)
meta.totalItems: The total amount of SomeEntity matching the filter conditions
meta.itemsPerPage: The requested items per page (i.e., the limit parameter)
meta.totalPages: The total amount of pages (based on the limit)
meta.currentPage: The current page this paginator "points" to
links.first: A URL for the first page to call | "" (blank) if no route is defined
links.previous: A URL for the previous page to call | "" (blank) if no previous to call
links.next: A URL for the next page to call | "" (blank) if no page to call
links.last: A URL for the last page to call | "" (blank) if no route is defined
Do note that
links.firstmay not have the 'page' query param defined
@Injectable()
export class CatService {
constructor(
@InjectRepository(CatEntity)
private readonly repository: Repository<CatEntity>,
) {}
async paginate(options: IPaginationOptions): Promise<Pagination<CatEntity>> {
return paginate<CatEntity>(this.repository, options, {
lives: 9,
});
}
}Eager loading should work with typeorm's eager property out the box. Like so
import { Entity, OneToMany } from 'typeorm';
@Entity()
export class CatEntity {
@OneToMany(t => TigerKingEntity, tigerKing.cats, {
eager: true,
})
tigerKings: TigerKingEntity[];
}
// service
class CatService {
constructor(private readonly repository: Repository<CatEntity>) {}
async paginate(page: number, limit: number): Promise<Pagination<CatEntity>> {
return paginate(this.repository, { page, limit });
}
}However, when using the query builder you'll have to hydrate the entities yourself. Here is a crude example that I've used in the past. It's not great but this is partially what typeORM will do.
const results = paginate(queryBuilder, { page, limit });
return new Pagination(
await Promise.all(
results.items.map(async (item: SomeEntity) => {
const hydrate = await this.someRepository.findByEntity(item);
item.hydrated = hydrate;
return item;
}),
),
results.meta,
results.links,
);const queryBuilder = this.repository
.createQueryBuilder<{ type: string; totalLives: string }>('c')
.select('c.type', 'type')
.addSelect('SUM(c.lives)', 'totalLives')
.groupBy('c.type')
.orderBy('c.type', 'DESC'); // Or whatever you need to do
return paginateRaw(queryBuilder, options);A similar approach is used for TypeORM's getRawAndEntities
Let's assume there's a joined table that matches each cat with its cat toys. And we want to bring how many toys each cat has.
const queryBuilder = this.repository
.createQueryBuilder<{ type: string; totalLives: string }>('cat')
.leftJoinAndSelect('cat.toys', 'toys')
.addSelect('COUNT(toys)::INTEGER', 'toyCount')
.groupBy('cat.name');This will allow us to get the paginated cats information with the additional raw query to build our actual response value. The return pagination object will be the same, but you're now able to handle or map the results and the raw objects as needed.
const [pagination, rawResults] = await paginateRawAndEntities(query, options);
pagination.items.map((item, index) => {
// we can do what we need with the items and raw results here
// change your items using rawResults.find(raw => raw.id === item.id)
});
return pagination;Since the values of the raw results will include all the joined table items as queried, you must make sure to handle the items as needed for your use case. Refer to TypeORM's getRawAndEntities implementation as needed.
The rawResults array will look something like this:
[
{ // Bobby appears 3 times due to the joined query
"cat_lives": 9,
"cat_type": "tabby",
"cat_name": "Bobby",
"toyCount": 3
},
{
"cat_lives": 9,
"cat_type": "tabby",
"cat_name": "Bobby",
"toyCount": 3
},
{
"cat_lives": 9,
"cat_type": "tabby",
"cat_name": "Bobby",
"toyCount": 3
},
{
"cat_lives": 2,
"cat_type": "Ginger",
"cat_name": "Garfield",
"toyCount": 1
},
...
]If you wanted to alter the meta data that is returned from the pagination object. Then use the metaTransformer in the options like so
class CustomPaginationMeta {
constructor(
public readonly count: number,
public readonly total: number,
) {}
}
return paginate<MyEntity, CustomPaginationMeta>(this.repository, {
page,
limit,
metaTransformer: (meta: IPaginationMeta): CustomPaginationMeta => new CustomPaginationMeta(
meta.itemCount,
meta.totalItems,
),
});This will result in the above returning CustomPaginationMeta in the meta property instead of the default IPaginationMeta.
If you want to alter the limit and/or page labels in meta links, then use routingLabels in the options like so
return paginate<MyEntity>(this.repository, {
page,
limit,
routingLabels: {
limitLabel: 'page-size', // default: limit
pageLabel: 'current-page', //default: page
}
});This will result links like http://example.com/something?current-page=1&page-size=3.