https://github.com/algebraic-graphs/typescript
Algebraic graphs implementation in TypeScript
https://github.com/algebraic-graphs/typescript
algebra algebraic fp fp-ts graph graphs
Last synced: 7 months ago
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Algebraic graphs implementation in TypeScript
- Host: GitHub
- URL: https://github.com/algebraic-graphs/typescript
- Owner: algebraic-graphs
- License: mit
- Created: 2020-01-31T11:33:29.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2023-03-03T12:35:30.000Z (over 2 years ago)
- Last Synced: 2025-03-21T15:18:53.635Z (8 months ago)
- Topics: algebra, algebraic, fp, fp-ts, graph, graphs
- Language: TypeScript
- Size: 330 KB
- Stars: 132
- Watchers: 5
- Forks: 4
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Algebraic graphs implementation in TypeScript
[](https://www.npmjs.com/package/alga-ts)
[](https://travis-ci.org/algebraic-graphs/typescript)
`alga-ts` is a library for algebraic construction and manipulation of graphs in TypeScript. This is a TypeScript port of [alga](https://github.com/snowleopard/alga) and [alga-scala](https://github.com/algebraic-graphs/scala).
> See [this Haskell Symposium paper](https://github.com/snowleopard/alga-paper) and the corresponding [talk](https://www.youtube.com/watch?v=EdQGLewU-8k) for the motivation behind the library, the underlying theory and implementation details. There is also a [Haskell eXchange talk](https://skillsmatter.com/skillscasts/10635-algebraic-graphs), and a [tutorial](https://nobrakal.github.io/alga-tutorial) by Alexandre Moine.
**N.B.** Please note that this project is WIP, so use it at your own discretion.
## Installation
The main library, `alga-ts`, is available at the NPM. As it uses [fp-ts](https://github.com/gcanti/fp-ts) for higher-kinded types, be sure to install it as well:
```sh
npm install --save alga-ts fp-ts
```
## Usage
To begin using `alga-ts`, you first need to obtain an instance of it's API for the given [Eq](https://dev.to/gcanti/getting-started-with-fp-ts-setoid-39f3) of your target data type. Consider the example:
```ts
import { getStructEq, eqNumber, eqString } from 'fp-ts/lib/Eq';
import { getInstanceFor } from 'alga-ts';
interface User {
name: string;
age: number;
}
const eqUser = getStructEq({
name: eqString,
age: eqNumber,
});
const G = getInstanceFor(eqUser);
```
Now `G` is a module containing all methods & constructors required to work with graphs of `User`:
```ts
const user1: User = { name: 'Alice', age: 32 };
const user2: User = { name: 'Bob', age: 41 };
const user3: User = { name: 'Charlie', age: 28 };
const graph1 = G.connect(
G.edge(user1, user2),
G.edge(user2, user3),
);
console.log(G.hasEdge(user1, user3, graph1)); // => true
```
### Pipeable graphs
Algbraic graphs happen to have type class instances for `Monad` (and, consequently, for `Functor` and `Applicative`) and `Alternative`. API instance, obtained via `getInstanceFor`, exposes methods from these type classes in a data-last form, so they could be used with `pipe` from `fp-ts`:
```ts
import { pipe } from 'fp-ts/lib/pipeable';
import { getInstanceFor } from 'alga-ts';
const GS = getInstanceFor(eqString);
...
const graph2 = pipe(
graph1,
G.map(u => u.name),
);
console.log(GS.hasEdge('Alice', 'Charlie', graph2)); // => true
```