@ng-draw-flow/core

NgDrawFlow

Import Dependencies and Register Node Components

To get started with the ng-draw-flow library, begin by setting up your module with the necessary imports and component registrations.

Add the NgDrawFlowComponent and ReactiveFormsModule to your module's imports array:

imports: [
  // ... (other necessary imports)
  NgDrawFlowComponent,
  ReactiveFormsModule,
];

Then, within the providers section, register the components that you want to be available for use as nodes within the graph editor:

app.module.ts

providers: [
  provideNgDrawFlowConfigs({
    yourNode: YourNodeComponent,
  }),
];

Set Up Data Model and Control for Graph Structure

In the component where you intend to construct your graph, you need to create a data structure that defines the nodes and connections.

app.component.ts

data: DfDataModel = {
  nodes: new Map(),
  connections: [],
};
form = new FormControl(this.data);

Next, link this data structure to your ng-draw-flow component using a FormControl. This will allow for reactive updates and interactions within your graph editor:

app.component.html

<ng-draw-flow [formControl]="form"></ng-draw-flow>

This setup ensures that your ng-draw-flow component is fully integrated with the Angular forms system, enabling seamless data flow and state management for your graph.

Populate Example DfDataModel

To illustrate how to set up the DfDataModel with actual data, the following example lays out a scenario with a collection of nodes and their connections:

app.component.ts

data: DfDataModel = {
  nodes: new Map()
    .set('node-1', {
      id: 'node-1',
      data: {type: 'yourNode', text: 'This base node'},
      position: {x: 0, y: 0},
      startNode: true,
    })
    .set('node-2', {id: 'node-2', data: {type: 'yourNode', text: 'This child node 1'}, position: {x: 250, y: 50}})
    .set('node-3', {id: 'node-3', data: {type: 'yourNode', text: 'This child node 2'}, position: {x: 250, y: -50}})
    .set('node-4', {
      id: 'node-4',
      data: {type: 'yourNode', text: 'This child node 3'},
      position: {x: 500, y: 0},
      endNode: true,
    }),
  connections: [
    {
      source: {nodeId: 'node-1', connectorType: DfConnectionPoint.Output, connectorId: 'node-1-output-1'},
      target: {nodeId: 'node-2', connectorType: DfConnectionPoint.Input, connectorId: 'node-2-input-1'},
    },
    {
      source: {nodeId: 'node-1', connectorType: DfConnectionPoint.Output, connectorId: 'node-1-output-1'},
      target: {nodeId: 'node-3', connectorType: DfConnectionPoint.Input, connectorId: 'node-3-input-1'},
    },
    {
      source: {nodeId: 'node-2', connectorType: DfConnectionPoint.Output, connectorId: 'node-2-output-1'},
      target: {nodeId: 'node-4', connectorType: DfConnectionPoint.Input, connectorId: 'node-4-input-1'},
    },
    {
      source: {nodeId: 'node-3', connectorType: DfConnectionPoint.Output, connectorId: 'node-3-output-1'},
      target: {nodeId: 'node-4', connectorType: DfConnectionPoint.Input, connectorId: 'node-4-input-1'},
    },
  ],
};

Each node mainly consists of an id, a position, and a data field. Inside the data field, you need to specify the node type that was previously registered and all the data you want to provide to the node.

The connections array contains objects that describe the start and end points of each connection. The source and target holds information about which node and specific connector are used for each connection.

Creating Custom Nodes

In ng-draw-flow, nodes can be customized to look and function just how you want them to. To create your own node, you should develop a component that extends from the NgDrawFlowBaseNode class. This component will incorporate directives such as DrawFlowInputDirective and DrawFlowOutputDirective.

import {NgIf} from '@angular/common';
import {ChangeDetectionStrategy, Component} from '@angular/core';
import {DfInputComponent, DfOutputComponent, DrawFlowBaseNode} from '@ng-draw-flow/core';

@Component({
  standalone: true,
  selector: 'app-your-node',
  imports: [NgIf, DfInputComponent, DfOutputComponent],
  templateUrl: './your-node.component.html',
  styleUrls: ['./your-node.component.less'],
  changeDetection: ChangeDetectionStrategy.OnPush,
})
export class YourNodeComponent extends DrawFlowBaseNode {}

.node {
  background: var(--tui-base-09);
  width: 10rem;
  box-shadow: var(--tui-shadow);
  border-radius: 0.5rem;
  padding: 0.5rem;
  border: 0.0625rem solid transparent;
  transition: border-color 0.2s ease-in-out;
  color: var(--tui-base-01);

  &.df-selected {
    border-color: var(--tui-background-accent-2);
  }
}

.input,
.output {
  position: absolute;
  z-index: 1;
}

.input {
  left: -0.5rem;
  top: 0.25rem;
}

.output-wrapper {
  position: relative;
}

.output {
  right: -0.5rem;
  top: 0;
}

<div
  class="node"
  [class.df-selected]="selected$ | async"
>
  <df-input
    class="input"
    *ngIf="!startNode"
    [connectorData]="{nodeId, connectorId: nodeId + '-input-1', single: false}"
  />

  <p class="tui-text_body-xs">{{ model.text }}</p>

  <df-output
    class="output"
    *ngIf="!endNode"
    [connectorData]="{nodeId, connectorId: nodeId + '-output-1', single: false}"
  />
</div>