querying.md

Filtering, sorting and pagination when querying data

Filtering and sorting are currently under construction

The system comes with builtin tools for pagination, filtering and sorting for efficiently displaying tabular data.

Guide

To enable pagination, extend the query class with the BaseQuery class like so

import { BaseQuery } from "src/core/query";

export class GetMonkiesQuery extends BaseQuery {}

and use the QueryService to fetch the desired data:

import { IQueryHandler, QueryHandler } from "@nestjs/cqrs";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";

import { QueryService } from "src/core/query";

import { Monkies } from "../../../infrastructure/entities/monkey.entity";
import { MonkeyDetails } from "../../contracts/dtos/journal-details.dto";
import { GetMonkiesQuery } from "../../contracts/queries/get-monkies.query";
import { mapToMonkeyDetails } from "../../mappers/monkey.mapper";

@QueryHandler(GetMonkeyQuery)
export class GetMonkeyHandler
  implements IQueryHandler<GetMonkiesQuery, MonkeyDetails[]>
{
  constructor(
    @InjectRepository(Monkey)
    private readonly monkies: Repository<Monkey>,
    private readonly queryService: QueryService<MonkeyEntry>,
  ) {}

  async execute(query: GetMonkiesQuery) {
    const foundMonkies = await this.queryService.find(this.monkies, { query });

    return mapToMonkeyDetails({ entries: foundMonkies });
  }
}

This will automatically include and handle the pagination parameters.