Topics

• Introduction
• Installation
• Getting started
• Query parameters
• API documentation

Introduction

Objection-find is a module for building search queries for objection.js models using HTTP query parameters. You can easily filter, order and page the result based on model's properties and relations using simple expressions. Relations can be eagerly fetched for the results using objection.js relation expressions.

Using objection-find in an express route is as easy as this:

var findQuery = require('objection-find');
// Our objection.js model.
var Person = require('../models/Person');

expressApp.get('/api/persons', function (req, res, next) {
  findQuery(Person)
    .allow(['firstName', 'movies.name', 'children.age', 'parent.lastName'])
    .allowEager('[children.movies, movies, parent.movies]')
    .build(req.query)
    .then(function (persons) {
      res.send(persons);
    })
    .catch(next);
});

Objection-find can be used with any node.js framework. Express is not a requirement. The route we just created can be used like this:

$http({
  method: 'GET',
  url: '/api/persons',

  // HTTP Query parameters.
  params: {
    // Select all persons whose first name starts with 'j' or 'J'
    'firstName:likeLower': 'J%',

    // And who have acted in the movie 'Silver Linings Playbook'.
    // This checks if the relation `movies` contains at least
    // one movie whose name equals 'Silver Linings Playbook'.
    'movies.name:eq': 'Silver Linings Playbook',

    // And who have at least one child younger than 10.
    // This checks if the relation `children` contains at least
    // one person whose age is less than 10.
    'children.age:lt': 10,

    // Order the result by person's parent's last name.
    // `parent` is a one-to-one relation.
    'orderBy': 'parent.lastName',

    // Fetch relations for the results. This is an objection.js
    // relation expression. Check out objection.js for more info.
    'eager': '[children, movies, parent.movies]',

    // Select a range starting from index 0
    'rangeStart': 0,

    // Select a range ending to index 4
    'rangeEnd': 4
  }
}).then(function (res) {
  var persons = res.data.results;

  console.log(persons.length); // --> 5
  console.log(persons[0].children);
  console.log(persons[0].movie);
  console.log(persons[0].parent.movies);

  // Total size of the result if the range wasn't given.
  console.log(res.data.total);
});

In our example Person model had a one-to-one relation parent, a many-to-many relation movies and one-to-many relation children. This example used the $http module of AngularJS but you can use objection-find with anything that can send an HTTP request.

Documentation on the supported query parameters can be found here and API documentation here.

Installation

npm install objection objection-find

Getting started

Easiest way to get started is to use the objection.js example project and copy paste this to the api.js file:

var findQuery = require('objection-find');

app.get('/persons/search', function (req, res, next) {
  findQuery(Person).build(req.query).then(function (persons) {
    res.send(persons);
  }).catch(next);
});

You also need to run this in the root of the example project to install objection-find:

npm install --save objection-find

Now you can start bombing the /persons/search route. Documentation on the supported query parameters can be found here.

Query parameters

Objection-find understands two kinds of query parameters: filters and special parameters.

Filters

A filter parameter has the following format:

<propertyReference>|<propertyReference>|...:<filter>=<value>

A propertyReference is either simply a property name like firstName or a reference to a relation's property like children.age (children is the name of the relation).

filter is one of the built-in filters eq, lt, lte, gt, gte, like, likeLower in, notNull or isNull. Filter can also be a custom filter registered using the registerFilter method.

The following examples explain how filter parameters work. For the examples, assume we have an objection.js model Person that has a one-to-one relation parent, a many-to-many relation movies and one-to-many relation children.

Filter query parameter	Explanation
firstName=Jennifer	Returns all Persons whose first name is 'Jennifer'.
firstName:eq=Jennifer	Returns all Persons whose first name is 'Jennifer'.
children.firstName:like=%rad%	Returns all Persons who have at least one child whose first name contains 'rad'.
`lastName	movies.name:like=%Gump%`
parent.age:lt=60	Returns all persons whose parent's age is less than 60.
parent.age:in=20,22,24	Returns all persons whose parent's age is 20, 22 or 24.

Filters are joined with AND operator so for example the query string:

firstName:eq=Jennifer&parent.age:lt=60&children.firstName:like=%rad%

would return the Persons whose firstName is 'Jennifer' and whose parent's age is less than 60 and who have at least one child whose name contains 'rad'.

Special parameters

In addition to the filter parameters, there is a set of query parameters that have a special meaning:

Special parameter	Explanation
eager=[children, parent.movies]	Which relations to fetch eagerly for the result models. An objection.js relation expression.
orderBy=firstName	Sort the result by certain property.
orderByDesc=firstName	Sort the result by certain property in descending order.
rangeStart=10	The start of the result range (inclusive). The result will be {total: 12343, results: [ ... ]}.
rangeEnd=50	The end of the result range (inclusive). The result will be {total: 12343, results: [ ... ]}.