This project created as simple replacement for projectstorm/react-diagrams.

What is it

React diagram is a collection of base components to create flow chart or process flow.

Live demo

What is included

• React components to implement base logic: Diagram, Node, Port, NodeDragZone
• callbacks to handle business logic: Port.canConnect, Port.onConnect, NodeDragZone.onMove
• base state handlers for: scroll, zoom, drag view, move nodes, connect ports.

Setup

npm i --save @mastir/react-diagram

How to use

import {
  CreateLinkState,
  DefaultState,
  Diagram,
  DragCanvasState,
  DragNodeState,
  EngineModel,
  ZoomHandler,
} from "@mastir/react-diagram";
import { Node, NodeDragZone, Port } from "@mastir/react-diagram";


    const engine = useMemo(() => {
        const engine = new EngineModel();
        engine.state.addStateHandler(new DefaultState());
        engine.state.addStateHandler(new CreateLinkState());
        engine.state.addStateHandler(new DragNodeState());
        engine.state.addStateHandler(new DragCanvasState());
        engine.state.actions.push(new ZoomHandler(engine));
        return engine;
    }, []);


    let node = {
        x: -85,
        y: -60,
        ports: [
          {name: 'First port!'},
          {name: 'Second port'},
        ]
    }
    
    let links = [];

    return <Diagram engine={engine} style={{minHeight:'100vh'}} links={links}>
        <Node model={node} position={[node.x,node.y]}>
              <NodeDragZone onMove={(x,y)=>{node.x=x;node.y=y}}>
                  <h1>Hello world!</h1>
              </NodeDragZone>
              {node.ports.map( (port,i) =>  <div key={i}>
                  <Port
                      key={i}
                      model={port}
                      canConnect={port2=>true}
                      onConnect={(port2,link) => {console.log('connect', port, port2, link); links.push(link)}}
                  >
                      <div style={{background:'#00F',width:16,height:16,display:'inline-block'}}/>
                  </Port>
                  {port.name}
              </div>)}
        </Node>
    </Diagram>;

Components

User defined types

TNode, TPort, TLink - unique string or any object representing element ( you should avoid object recreation or duplication )

Diagram

Root component

prop	type	description
engine*	EngineModel	Main diagram container
links*	TLink[]	List of all links to display
createLink	(TPort)=>TLink	TLink factory
getLinkStyle	(TLink) => style	default {color:'#FFF', width: 2, curviness: 50}
linksLayer	React.Element	You can pass LinksLayer state handler wrap component (to avoid whole diagram redraw on link updates)

Node

Container for any element placed in Diagram

prop	type	description
model*	TNode	any object represented by this element
position*	[number,number]	node position x axis
key	string	required for all nodes, its recomended to use any generated id

Port

Container for connectors in Node

prop	type	description
model*	TPort	any object represented by this element
linkOffset	[number,number]	link connection point ([-1,1] = left bottom, [0,-1] = center,top), default = [0, 0]
createLink	()=>TLink	new TLink factory, created from this port
canConnect	(TPort, TLink)=>boolean	default: ()=>true
onConnect	(TPort, TLink)=>void	callback for new link connection

NodeDragZone

prop	type	description
onMove	(x,y)=>void	callback for node move end

LinksLayer

react component to render links in svg

EngineModel

This is core container of the diagram. Engine contains 3 services: canvas, state, links

CanvasModel

Contain information about currently rendered elements and provide methods to work with coordinates and elements

StateMachineModel

Event processing service, active state handler can trigger state transitions. All of the action logic (zoom, drag canvas, move node, create link) realised in state handlers and can be extended and customized.

LinkListModel

Contain information about rendered TLink[] models and methods to redraw them