Nest PSF (Page, Sort, Filter)

Nest PSF is a library that provides helpers for easy pagination, sorting, and filtering for your API.

Getting Started

Install the package.

npm install --save nestjs-psf

Use in your controller

@Get('')
async index(
  @Paginate() paginateParams: PaginateParams,
  @SortAndFilter() sortAndFilterParams: SortAndFilterParams
): Promise<Paginated<Agent>> {
  return await this.agentRepository
    .createQueryBuilder('agent')
    .sortAndFilter(sortAndFilterParams)
    .paginate(paginateParams);
}

That's it! Your API now supports:

• pagination, with the page and pageSize query params
• sorting, with the sort query param
• and filtering, with the filter query param.

When using the parameter decorators in your controllers it is good practice to set a maximum page size, and to whitelist which attributes are sortable and filtering, like so:

@Paginate({
  maxPageSize: 100
}) paginateParams: PaginateParams,
@SortAndFilter({
  sortable: ['name', 'email'],
  filterable: ['name', 'createdAt'],
}) sortAndFilterParams: SortAndFilterParams

For details on each of these, see below.

Pagination

For pagination, the parameter decorator to use in your controller is the @Paginate decorator. This will give you a PaginateParams to pass to the paginate method of choice. We provide the ability to paginate using a repository, or using the query builder.

// for query builder we use .paginate instead of .getMany
await this.someRepository
  .createQueryBuilder()
  .paginate(paginateParams);

// for repository we use the provided paginate helper
await paginate(this.someRepository, paginateParams);

// you can pass regular repository FindOptions as the 3rd param,
// this is the same as if you were calling repo.find()
await paginate(this.someRepository, paginateParams, {
  where: { age: MoreThan(5) }
});

After enabling pagination on your api, the endpoint will accept page and pageSize query parameters. An example call would be like http://localhost/api/some_api?page=2&pageSize=2

You will receive a response back like:

{
  results: [
    {
      id: 1,
      name: 'Name 1',
    },
    {
      id: 2,
      name: 'Name 2',
    }
  ],
  meta: { pageCount: 5, pageSize: 2, page: 2, count: 9 },
  links: {
    first: 'http://127.0.0.1:36285/api/some_api?pageSize=2&page=1',
    next: 'http://127.0.0.1:36285/api/some_api?pageSize=2&page=3',
    prev: 'http://127.0.0.1:36285/api/some_api?pageSize=2&page=1',
    last: 'http://127.0.0.1:36285/api/some_api?pageSize=2&page=5'
  }
}

We provide links that allow you to easily go to the next/prev/first/last page. Note that next will be null if there is no next page, and prev will be null if there is no previous page.

Additionally we provide metainformation, for you to display page counts, record counts, etc.

Sort And Filter

Sorting and filtering both use the @SortAndFilter decorator, which will give you a SortAndFilterParams to pass to your choice of helper.

// for query builder we use .sortAndFilter
await this.someRepository
  .createQueryBuilder()
  .sortAndFilter(sortAndFilterParams)
  .getMany();

// you can use the sortAndFilter helper to make a FindOptions
// for use in the repository .find method
await this.someRepository.find(sortAndFilter(sortAndFilterParams))

This can also be combined with pagination.

// query builder
await this.someRepository
  .createQueryBuilder()
  .sortAndFilter(sortAndFilterParams)
  .paginate(paginateParams);

// repository
await paginate(this.someRepository, paginateParams, sortAndFilter(sortAndFilterParams));

Sorting

When you enable sorting on your api endpoint, the endpoint will now accept a sort query parameter.

The sort query parameter accepts a comma seperated list of fields to order by. To reverse a sort column, prefix it with a -

Usage example:

http://localhost/api/some_api?sort=name,-email

You can also sort across ManyToOne relationships by using dot notation. Note that this only works if you are using the Query Builder helps due to TypeORM limitations:

http://localhost/api/some_api?sort=profile.name

Filtering

By enabling filtering on your API endpoint you enable a range of available searches, the general format for such a search is:

http://localhost/api/some_api?filter=attr__operator:search

You can filter against multiple attribute by separating them with columns, for example:

http://localhost/api/some_api?filter=name__icontains:bob,age__gt:25

A list of all operators are as follows:

Query Param Operator	Effect
eq	exactly equals to
neq	not exactle equals to
contains	contains somewhere within it
icontains	case insentive contains
gt	greater than
lt	less than
gte	greater than or equal to
lte	less than or equal to
startswith	starts with
endswith	ends with