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count

统计满足条件的实体数量。

方法签名​

count(options: CountOptions<T>): Observable<number>

参数​

interface CountOptions<T> {
  where: RuleGroup<InstanceType<T>>;
}

示例​

基础计数​

import { firstValueFrom } from 'rxjs';

const total = await firstValueFrom(Todo.count({ where: { combinator: 'and', rules: [] } }));

条件计数​

const completed = await firstValueFrom(
  Todo.count({
    where: {
      combinator: 'and',
      rules: [{ field: 'completed', operator: '=', value: true }]
    }
  })
);

搭配分页​

async function getPagedTodos(page: number, pageSize: number) {
  const where = { combinator: 'and' as const, rules: [] };

  const [items, total] = await Promise.all([
    firstValueFrom(
      Todo.find({
        where,
        orderBy: [{ field: 'createdAt', sort: 'desc' }],
        limit: pageSize,
        offset: (page - 1) * pageSize
      })
    ),
    firstValueFrom(Todo.count({ where }))
  ]);

  return { items, total, page, pageSize, totalPages: Math.ceil(total / pageSize) };
}

关系字段​

const userTodoCount = await firstValueFrom(
  Todo.count({
    where: {
      combinator: 'and',
      rules: [{ field: 'owner.id', operator: '=', value: userId }]
    }
  })
);