Package Exports

@loopback/filter
@loopback/filter/dist/index.js

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Readme

@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

{% include note.html content="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