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Loopback Distinct mixin for MongoDB

Provide to models the ability to query distinct values from database

This is a Loopback mixin to be used together with MongoDB connector. Works for Loopback 2 and 3.

How to install

Install the package through NPM

npm i -S @aliatech/loopback-mongo-distinct-mixin

or Yarn

yarn add --prod @aliatech/loopback-mongo-distinct-mixin

Server configuration

Include the mixin in server/model-config.json:

  "_meta": {
    "sources": [
    "mixins": [


Enable the mixin in your model definition, ie person.json.

Basic configuration

  "name": "Person",
  "properties": {
    "name": "string",
    "company": "string"
  "mixins": {
    "Distinct": true

Now you can query for distinct values this way:

app.models.Person.distinctValues('name', (err, names) => {
  if (err) return next(err);
  // names = ['john', 'mary', 'anne', ...]

Or using promise:

  .then((names) => {
    // names = ['john', 'mary', 'anne', ...]
  .catch((err) => {
    // handle an error

Advanced configuration

Enable the mixin passing an options object instead of just true.

These are the available options:

Option Type Required Description
defaultProperty string optional Default property name to get values. With this option, it won't be required to specify property argument.
remote object optional Customize a remote method to call distinct feature.
remote.enabled boolean optional Enable a remote method for distinctValues. (default false) string optional Name of the remote method. (default 'distinctValues')
remote.definition object optional The Loopback definition of the remote method.

Default options

These are the default options that will be merged with the model specifics:

  "remote": {
    "enabled": false,
    "name": "distinctValues",
    "definition": {
      "description": "Find objects with distinct property",
      "http": {
        "path": "/distinctValues",
        "verb": "get"
      "accepts": [{
        "arg": "property",
        "type": "string",
        "required": true
      }, {
        "arg": "where",
        "type": "object",
        "required": false
      "returns": {
        "arg": "objects",
        "type": "array",
        "root": true

Note that property argument will required only if defaultProperty is not set.

Advanced usage

Call distinct values with filter.

app.models.Person.distinctValues('name', {company: 'alia'}, (err, names) => {
  // Got distinct names for objects having company = 'alia'

Note: Filter should be MongoDB native, not Loopback

Call distinct values using a default property.

  1. Configure defaultProperty option
  2. Call distinctValues omitting property argument
app.models.Person.distinctValues((err, names) => {
  // Do something

Using default property and a filter:

app.models.Person.distinctValues({company: 'alia'}, (err, names) => {
  // Do something

Remote distinctValues

  1. Configure remote.enabled option to be true
  2. Call through the API
const request = require('request');
  {qs: {property: 'name', where: {company: 'alia'}}},
  (err, res, body) => {
    if (err) return next(err);
    if (res.statusCode === 200){
      const names = JSON.parse(body);
      // Do something


Install develop dependences

npm i -D # If you use NPM 
yarn install # If you use Yarn 

Execute tests

npm test # Without coverage check 
npm run test-with-coverage # With coverage check 


Developed by Juan Costa for ALIA Technologies

ALIA Technologies


npm i @aliatech/loopback-mongo-distinct-mixin

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