"Exploring the world of Typescript with the Drawflow library

Question

"Exploring the world of Typescript with the Drawflow library

Currently, I am integrating the fantastic Drawflow library created by @Jerosoler (available at: https://github.com/jerosoler/Drawflow) into my PrimeNg project.

User @BobBDE has provided typescript definitions for this library here: https://www.npmjs.com/package/@types/drawflow

My project utilizes PrimeNg with Angular 11 and Typescript 4.

I have successfully installed both the library and the definitions using npm commands. Everything seems to be in order as I can locate the JS library, and the definitions to use within Typescript.

Nevertheless, I am encountering an undefined error and I am having difficulty identifying what could possibly be incorrect...

In my component's HTML, I have included the following:

<div #drawflowDiv></div>

To access the div in my component's Typescript:

@ViewChild('drawflowDiv', {static: true}) 
drawflowDiv: HTMLElement;

Subsequently, in my ngOnInit function, I have the following setup:

ngOnInit(): void {
    console.log(this.drawflowDiv);
    const editor = new drawflow(this.drawflowDiv);
    editor.reroute = true;
    editor.editor_mode = 'edit';
    editor.drawflow = {.....}; // Default example JSON for the library
    editor.start();
}

There are no errors evident in the code, and the drawflow library is correctly connected. The console.log provides all the details of the HTML element within the div, indicating that it is not undefined. A screenshot of the console log is attached to this post.

Your assistance would be greatly appreciated, and I hope that someone here might have a solution.

Thanks in advance!

View screenshot of console output here

angular typescript npm undefined primeng

Answer 1

Answer №1

For a more reusable approach, consider encapsulating the code within a directive:

Directive file: app-draw-flow.directive.ts

import { Directive, ElementRef, OnInit } from '@angular/core';
import Drawflow from 'drawflow';

@Directive({
  selector: '[appDrawFlow]'
})
export class DrawFlowDirective implements OnInit {

  editor: Drawflow;

  constructor(private hostElementRef: ElementRef) { }

  ngOnInit() {
    if (!!this.hostElementRef?.nativeElement) {
      const { nativeElement } = this.hostElementRef;
      this.initializeDrawFlow(nativeElement);
    }
  }

  private initializeDrawFlow(element: HTMLElement): void {
    try {
      if (!!element) {
        this.editor = new Drawflow(element);
        this.editor.reroute = true;
        this.editor.editor_mode = 'edit';
        // this.editor.drawflow = {}
        this.editor.start();
      } else {
        console.error('Drawflow host element does not exist');
      }

    } catch (error) {
      console.error('Unable to start Drawflow', error);
    }
  }
}

Don't forget to include DrawFlowDirective as a declaration in the parent feature module where you plan to use it.

Here's an example of how to use it in your template:

<div appDrawFlow></div>

If you encounter any issues running it, verify your module declarations. Here is an example (partial snippet of app module):

@NgModule(
  {declarations: [DrawFlowDirective]}
)
export class AppModule { }

Answer 2

For a more reusable approach, consider encapsulating the code within a directive:

Directive file: app-draw-flow.directive.ts

import { Directive, ElementRef, OnInit } from '@angular/core';
import Drawflow from 'drawflow';

@Directive({
  selector: '[appDrawFlow]'
})
export class DrawFlowDirective implements OnInit {

  editor: Drawflow;

  constructor(private hostElementRef: ElementRef) { }

  ngOnInit() {
    if (!!this.hostElementRef?.nativeElement) {
      const { nativeElement } = this.hostElementRef;
      this.initializeDrawFlow(nativeElement);
    }
  }

  private initializeDrawFlow(element: HTMLElement): void {
    try {
      if (!!element) {
        this.editor = new Drawflow(element);
        this.editor.reroute = true;
        this.editor.editor_mode = 'edit';
        // this.editor.drawflow = {}
        this.editor.start();
      } else {
        console.error('Drawflow host element does not exist');
      }

    } catch (error) {
      console.error('Unable to start Drawflow', error);
    }
  }
}

Don't forget to include DrawFlowDirective as a declaration in the parent feature module where you plan to use it.

Here's an example of how to use it in your template:

<div appDrawFlow></div>

If you encounter any issues running it, verify your module declarations. Here is an example (partial snippet of app module):

@NgModule(
  {declarations: [DrawFlowDirective]}
)
export class AppModule { }

Answer 3

Answer №2

To include a drawing flow in your HTML component, simply add the following code:

<div id="drawflowContainer"></div>

Then, in the ngOnInit function:

this.drawFlowChart = new Drawflow(document.getElementById('drawflowContainer'));
this.drawFlowChart.initialize();
...

Answer 4

To include a drawing flow in your HTML component, simply add the following code:

<div id="drawflowContainer"></div>

Then, in the ngOnInit function:

this.drawFlowChart = new Drawflow(document.getElementById('drawflowContainer'));
this.drawFlowChart.initialize();
...

Answer 5

Answer №3

To properly initialize your editor, make sure to include the nativeElement in its creation:

Ensure that when you instantiate the drawflow editor, you pass in this.drawflowDiv.nativeElement like this:
const editor = new drawflow(this.drawflowDiv.nativeElement);

Answer 6

To properly initialize your editor, make sure to include the nativeElement in its creation:

Ensure that when you instantiate the drawflow editor, you pass in this.drawflowDiv.nativeElement like this:
const editor = new drawflow(this.drawflowDiv.nativeElement);

"Exploring the world of Typescript with the Drawflow library

Answer №1

Answer №2

Answer №3

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