@loopback/filter
A set of utility typings and filter builders to aid in constructing LoopBack filters using the builder pattern.
Overview
This lightweight module provides strongly-typed typings and filter builders to intuitively construct LoopBack filters to be used against querying a LoopBack filter-compatible server over the network or within the server itself.
Installation
Note:
Already installed @loopback/repository
? Import from there instead. This package is meant for standalone use without @loopback/repository
.
npm install --save @loopback/filter
Basic use
WhereBuilder
The WhereBuilder
is a builder specifically meant to construct the where
portion of the filter.
import {WhereBuilder} from '@loopback/filter';
const whereBuilder = new WhereBuilder();
const where = whereBuilder
.between('price', 99, 299)
.and({brand: 'LoopBack'}, {discount: {lt: 20}})
.or({instock: true})
.build();
FilterBuilder
The FilterBuilder
is a builder to construct the filter as a whole.
import {FilterBuilder} from '@loopback/filter';
const filterBuilder = new FilterBuilder();
const filter = filterBuilder
.fields('id', 'a', 'b')
.limit(10)
.offset(0)
.order(['a ASC', 'b DESC'])
.where({id: 1})
.build();
FilterBuilder.where()
also accepts an instance of WhereBuilder
.
const filterBuilder = new FilterBuilder();
const filter = filterBuilder
// ...
.where(where)
.build();
Advanced use
Strong typings
The FilterBuilder
and WhereBuilder
accept a model or any string-based key
objects’ typing for strong typings:
/**
* Everything was imported from `@loopback/repository` as `@loopback/filter`
* is re-exported in that package.
**/
import {
FilterBuilder,
model,
property,
WhereBuilder,
} from '@loopback/repository';
@model()
class Todo extends Entity {
@property({id: true})
id: number;
@property()
title: string;
@property()
description: string;
@property()
priority: number;
}
const whereBuilder = new WhereBuilder<Todo>();
const where = whereBuilder.between('priority', 1, 3).build();
const filterBuilder = new FilterBuilder<Todo>();
const filter = filterBuilder
.fields('id', 'title')
.order(['title DESC'])
.where(where)
.build();
API docs
See the API docs for FilterBuilder and WhereBuilder for more details on the full API.
Contributions
Tests
Run npm test
from the root folder.
Contributors
See all contributors.
License
MIT