https://github.com/liitfr/relational-reselect
🤝 A declarative way to express queries with reselect
https://github.com/liitfr/relational-reselect
immutablejs join redux relational-algebra relationship reselect selector
Last synced: 22 days ago
JSON representation
🤝 A declarative way to express queries with reselect
- Host: GitHub
- URL: https://github.com/liitfr/relational-reselect
- Owner: liitfr
- License: mit
- Created: 2019-04-21T23:06:09.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2023-01-03T20:17:45.000Z (over 2 years ago)
- Last Synced: 2024-10-14T01:04:49.642Z (7 months ago)
- Topics: immutablejs, join, redux, relational-algebra, relationship, reselect, selector
- Language: TypeScript
- Homepage:
- Size: 1.49 MB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 16
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
Awesome Lists containing this project
README
# relational-reselect
[](https://travis-ci.org/liitfr/relational-reselect)
[](https://coveralls.io/github/liitfr/relational-reselect?branch=master)
[](https://app.codacy.com/app/liitfr/relational-reselect?utm_source=github.com&utm_medium=referral&utm_content=liitfr/relational-reselect&utm_campaign=Badge_Grade_Dashboard)
With its decarative style, this library aims to facilitate creation of complex selectors on a normalized store that imposes to perform joins, lookups, relationships, or whatever you call it !
```js
import { createSelector } from 'reselect';
import Query from 'relational-reselect';
// my selectors
const a = createSelector(
aSelector,
aFn,
);
const b = createSelector(
bSelector,
bFn,
);
const c = createSelector(
cSelector,
cFn,
);
// define my query
const myQuery = new Query()
.from(a, 'a')
.leftJoin(b, 'b')
.on(row => row.getIn(['a', 'id']) === row.getIn(['b', 'aRef']))
.leftJoin(c, 'c')
.on(row => row.getIn(['c', 'id']) >= row.getIn(['a', 'cId']));
// get generated selector
const mySelector = myQuery.get();
// or directly run it
const myData = myQuery.run(state);
```
other examples are available on dedicated [CodeSandbox](https://codesandbox.io/s/427q264yv0)
## Install
```js
npm install --save relational-reselect
```
## How to write a query ?
## API
### Query bloc
#### `new Query()`
Create a new query
#### `get(): Selector`
generate selector for this query
#### `run(state: State): Collection`
run this query (= execute its selector) and return result
### Select bloc
#### `select(selectSpec: SpecificationForTuple): Select`
Optional operation if you need to process data coming from From bloc.
### From bloc
In this bloc, any `dataSource` can be a selector (a simple one or a `reselect` one) or another valid query if you need to nest them.
`Aliases` are required for naming `dataSources`, except when you use `except`, `intersect`, and `union` joins
#### `from(dataSource: DataSource, alias: string): From`
Required operation.
#### Joins
Optional operation. You can join as much data sources as you want as long as you specify how to join them.
Supported join types are :
- `innerJoin(dataSource: DataSource, alias: string): IncompleteJoin`
- `leftJoin(dataSource: DataSource, alias: string): IncompleteJoin`
- `rightJoin(dataSource: DataSource, alias: string): IncompleteJoin`
- `fullJoin(dataSource: DataSource, alias: string): IncompleteJoin`
- `except(dataSource: DataSource): CompleteJoin`
- `intersect(dataSource: DataSource): CompleteJoin`
- `union(dataSource: DataSource): CompleteJoin`
- `cartesian(dataSource: DataSource, alias: string): CompleteJoin`
Incomplete joins need to be completed with a `on(specification: SpecificationForMatchingTuple): CompleteJoin`
### Where bloc
#### `where(whereSpec: SpecificationForMatchingTuple): Where`
Optional operation. This filter will be applied over data coming from From or Select (if exists) bloc
### Ordering bloc
#### `orderBy(orderBySpec: SpecificationForOrderingTuples): OrderBy`
Optional operation. This sort will be applied over data coming from From, or Select (if exists), or Where (if exists) bloc
### Grouping bloc
TODO !
### Specification Types
```
type Tuple = Map;
type SpecificationForTuple = (tuple: Tuple) => Tuple;
type SpecificationForMatchingTuple = (tuple: Tuple) => boolean;
type SpecificationForOrderingTuples = (left: Tuple, right: Tuple) => number;
```
## Class Diagram
