Pagination, Sorting, Limiting, and Selecting

All official database adapters support a common way for sorting, limiting, selecting, and paginating find method calls as part of params.query.

Pagination

When initializing an adapter you can set the following pagination options in the paginate object:

• default - Sets the default number of items
• max - Sets the maximum allowed number of items per page (even if the $limit query parameter is set higher)

When paginate.default is set, find will return an object (instead of the normal array) in the following form:

{
  "total": "<total number of records>",
  "limit": "<max number of items per page>",
  "skip": "<number of skipped items (offset)>",
  "data": [/* data */]
}

The pagination options can be set as follows:

const service = require('feathers-<db-name>');

// Set the `paginate` option during initialization
app.use('/todos', service({
  paginate: {
    default: 5,
    max: 25
  }
}));

// override pagination in `params.paginate`
app.service('todos').find({
  paginate: {
    default: 100,
    max: 200
  }
});
// disable pagination for this call
app.service('todos').find({
  paginate: false
});

Note: Disabling the pagination is not available in the client. Only query is passed to the server. (Workaround)

Sorting, limiting and selecting

The find API allows the use of $limit, $skip, $sort, and $select in the query. These special parameters can be passed directly inside the query object:

// Find all recipes that include salt, limit to 10, only include name field.
{"ingredients":"salt", "$limit":10, "$select": ["name"] } } // JSON

GET /?ingredients=salt&$limit=10&$select[]=name // HTTP

ProTip: As a result of allowing these to be put directly into the query string, you won't want to use $limit, $skip, $sort, or $select as field names for documents in your database.

$limit

$limit will return only the number of results you specify:

// Retrieves the first two records found where age is 37.
query: {
  age: 37,
  $limit: 2
}

$skip

$skip will skip the specified number of results:

// Retrieves all except the first two records found where age is 37.
query: {
  age: 37,
  $skip: 2
}

$sort

$sort will sort based on the object you provide:

// Retrieves all where age is 37, sorted ascending alphabetically by name.
query: {
  age: 37,
  $sort: { name: 1 }
}

// Retrieves all where age is 37, sorted descending alphabetically by name.
query: {
  age: 37,
  $sort: { name: -1}
}

$select

$select support in a query allows you to pick which fields to include in the results.

// Only retrieve `name` and `id`
query: {
  name: 'Alice',
  $select: ['id', 'name']
}

To exclude fields from a result the remove hook can be used.