Drupal JSON-API Params

The JSON:API is part of Drupal Core.

The JSON:API specifications defines standard query parameters to be used to do filtering, sorting, restricting fields that are returned, pagination and so on.

This module provides a helper Class to create the required query. While doing so, it also tries to optimise the query by using the short form, whenever possible.

Installation

Install the package via npm:

$ npm i drupal-jsonapi-params

Usage

import

Import DrupalJsonApiParams from drupal-jsonapi-params

import {DrupalJsonApiParams} from 'drupal-jsonapi-params';

const apiParams = new DrupalJsonApiParams();

require

var drupalJsonapiParams = require("drupal-jsonapi-params")

const apiParams = new drupalJsonapiParams.DrupalJsonApiParams();

apiParams
  // Add Group within Groups.
  .addGroup('publish_status', 'OR', 'parent_group')
  .addGroup('child_group_B', 'AND', 'parent_group')
  .addGroup('parent_group', 'AND')
  // Add Filters.
  .addFilter('status', '1')
  // Add Filter to Group.
  .addFilter('status', '2', '!=', 'publish_status')
  // Add Page Limit.
  .addPageLimit(5)
  // Add Page Offset.
  .addPageOffset(20)
  // Add Fields.
  .addFields('node--article', ['field_a.id', 'field_b.uid', 'field_c.tid'])
  // Add Includes.
  .addInclude(['field_a.id', 'field_b.uid', 'field_c.tid'])
  // Add multiple sort criterion.
  .addSort('id', 'DESC')
  .addSort('uid')
  .addSort('status');

const urlencodedQueryString = apiParams.getQueryString();
const queryString = apiParams.getQueryString({ encode: false });

API

getQueryString [options?]

Returns query string which can be used in api calls. By default the output is URI encoded. Options can be passed to control the qs.stringifying internally used.

addFilter

Used to restrict items returned in a listing.

Params	Type	Description
path	string	A 'path' identifies a field on a resource
value	string	string[]
operator	string	(Optional) An 'operator' is a method of comparison
group	string	(Optional) Name of the group, the filter belongs to

Following values can be used for the operator. If none is provided, it assumes "=" by default.

  '=', '<>',
  '>', '>=', '<', '<=',
  'STARTS_WITH', 'CONTAINS', 'ENDS_WITH',
  'IN', 'NOT IN',
  'BETWEEN', 'NOT BETWEEN',
  'IS NULL', 'IS NOT NULL'

NOTE: Make sure you match the value supplied based on the operators used as per the table below

Value Type	Operator	Description
string	=, <>, >, >=, <, <=, STARTS_WITH, CONTAINS, ENDS_WITH
string[]	IN, NOT IN
string[] size 2	BETWEEN, NOT BETWEEN	The first item is used for min (start of the range), and the second item is used for max (end of the range).
null	IS NULL, IS NOT NULL	Must use null

Read more about filter in Drupal.org Documentation

addGroup

Used to group Filters. Groups can be nested too.

Params	Type	Description
name	string	Name of the group
conjunction	string	(Optional) All groups have conjunctions and a conjunction is either AND or OR.
memberOf	string	(Optional) Name of the group, this group belongs to

addInclude

Used to add referenced resources inside same request. Thereby preventing additional api calls.

Params	Type	Description
fields	string[]	Array of field names

Read more about Includes in Drupal.org Documentation

addSort

Used to return the list of items in specific order.

Params	Type	Description
path	string	A 'path' identifies a field on a resource
direction	string	Sort direction ASC or DESC

Read more about Sort in Drupal.org Documentation

addPageLimit

Use to restrict max amount of items returned in the listing. Using this for pagination is tricky, and make sure you read the following document on Drupal.org to implement it correctly.

Params	Type	Description
limit	number	Number of items to limit to

Read more about Pagination in Drupal.org Documentation

addPageOffset

Use to skip some items items from start of the listing. Please note that this is not the page number. To get the offset number for a page you can multiply the number of pages you want to skip with items per page.

Params	Type	Description
offset	number	Number of items to skip to

Read more about Pagination in Drupal.org Documentation

NOTE

JSON:API response have pagination information build into the response. Based on the results in the response, you can get "previous" and "next" links which can be used to get further items when results overflows into multiple pages.

If you are looking for a practical guide, you can check out the example in this issue on GitHub #40

addFields

The name of this method might be misleading. Use this to explicitely request for specific fields on an entity.

Params	Type	Description
type	string	Resource type
fields	string[]	Array of field names in the given resource type

---

addCustomParam

Use to add custom parameter to the query.

Params	Type	Description
input	object	The parameter object

E.g. usage

apiParams
  // To add `foo=bar` to the query.
  .addCustomParam({foo: 'bar'})
  // To add `foo[bar]=baz` to the query.
  .addCustomParam({ foo: {bar: 'baz'}})
  // To add `bar[0]=a&bar[1]=b&bar[2]=c` to the query.
  .addCustomParam({ bar: ['a', 'b', 'c']})

Helper methods

clear

Clears all query parameter constructed so far.

getQueryObject

Get object representation of the query object generated so far.

initialize

Re-initialize with a query string/object or another instance of DrupalJsonApiParams

initializeWithQueryObject

Re-initialize with previously stored data from getQueryObject

initializeWithQueryString

Re-initialize with previously stored data from getQueryString. This method accepts an optional parameter to pass options to qs library when parsing the given query.

Please refer to https://www.npmjs.com/package/qs for more info about available options.

This would override any options set using setQsOptions during the given call.

setQsOption

Set options that is passed to qs library when parsing/serializing query paramters. Please refer to https://www.npmjs.com/package/qs for more info about available options.

getQsOption

Get options that is passed to qs library when parsing/serializing query paramters. The value should match whatever was previously set via setQsOptions method.