@motech-development/pagination/lib/index.esm.js

NestJS pagination utility

import { createParamDecorator, Injectable, Module } from '@nestjs/common';
import { map } from 'rxjs/operators';

var PaginationEnum;

(function (PaginationEnum) {
  PaginationEnum["Asc"] = "asc";
  PaginationEnum["Desc"] = "desc";
  PaginationEnum[PaginationEnum["Max"] = 50] = "Max";
  PaginationEnum[PaginationEnum["Min"] = 5] = "Min";
  PaginationEnum[PaginationEnum["Page"] = 1] = "Page";
  PaginationEnum[PaginationEnum["Size"] = 10] = "Size";
})(PaginationEnum || (PaginationEnum = {}));

var PaginationEnum$1 = PaginationEnum;

/**
 * Calculates the number of items to take and ensures min and max ranges are respected.
 *
 * @param limit - Number of items to return.
 * @returns Number of items to take.
 */

const calculateTake = limit => {
  const value = Number(limit);

  if (value > PaginationEnum$1.Max) {
    return PaginationEnum$1.Max;
  }

  if (value < PaginationEnum$1.Min) {
    return PaginationEnum$1.Min;
  }

  return value;
};
/**
 * Calculates how many items to skip based on page number and items to take.
 *
 * @param page - Page number.
 * @param take - Number of items to take.
 * @returns Number of items to skip.
 */

const calculateSkip = (page, take) => {
  const value = Number(page);
  return take * (value - 1);
};
/** Ordering object. */

/**
 * Generates order by object.
 *
 * @param dir - Direction to order results by.
 * @param sortBy - Property to sort by.
 * @returns Order by object
 */
const calculateOrderBy = (dir, sortBy) => {
  if (sortBy) {
    const value = String(sortBy);
    return {
      [value]: dir
    };
  }

  return {};
};
const calculatePages = (total, limit) => total > 0 ? Math.ceil(total / limit) : 0;

/** Paginated query object. */

/**
 * Pagination decorator factory.
 *
 * @param _ - Decorator data.
 * @param ctx - Execution context.
 * @returns Pagination query object.
 */
const paginationFactory = (_, ctx) => {
  const {
    query
  } = ctx.switchToHttp().getRequest();
  const {
    dir = PaginationEnum$1.Desc,
    limit = PaginationEnum$1.Size,
    page = PaginationEnum$1.Page,
    sortBy
  } = query;
  const take = calculateTake(limit);
  const skip = calculateSkip(page, take);
  const orderBy = calculateOrderBy(dir, sortBy);
  return {
    orderBy,
    skip,
    take
  };
};
/**
 * Pagination decorator. Generates paginated query from query params.
 */

const Pagination = createParamDecorator(paginationFactory);

var _dec$1, _class$1;
/** Paginated result DTO. */

/**
 * Transforms response into a paginated response.
 */
let PaginationInterceptor = (_dec$1 = Injectable(), _dec$1(_class$1 = class PaginationInterceptor {
  intercept(ctx, next) {
    const {
      query
    } = ctx.switchToHttp().getRequest();
    const {
      limit = PaginationEnum$1.Size,
      page = PaginationEnum$1.Page
    } = query;
    const take = calculateTake(limit);
    return next.handle().pipe(map(([total, items]) => {
      const pages = calculatePages(total, take);
      return {
        items,
        limit: take,
        page: Number(page),
        pages,
        total
      };
    }));
  }

}) || _class$1);

var _dec, _class;
/**
 * Pagination module.
 */

let PaginationModule = (_dec = Module({
  exports: [PaginationInterceptor],
  providers: [PaginationInterceptor]
}), _dec(_class = class PaginationModule {}) || _class);

export { Pagination, PaginationInterceptor, PaginationModule };
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