Incorporating CodeMirror into Angular2 using TypeScript

Question

Incorporating CodeMirror into Angular2 using TypeScript

I've been working on integrating a CodeMirror editor into an Angular2 project, but I'm encountering some issues with the instantiation of the editor. Here is my code snippet:

editor.component.ts

import {Component} from 'angular2/core'
import {BrowserDomAdapter} from 'angular2/platform/browser'

declare var CodeMirror: any;

@Component({
    selector: 'editor',
    templateUrl: './meang2app/partials/editor.html'
})

export class Editor{
    dom: BrowserDomAdapter;
    editor: any;
    constructor(){
        this.dom = new BrowserDomAdapter();
        this.editor = new CodeMirror.fromTextArea(this.dom.query("textarea"), {lineNumbers: true, mode: {name: "javascript", globalVars: true}});
    }
}

editor.html

<textarea id="code" name="code">
    <!-- Where a CodeMirror instance should be rendered -->
</textarea>

In my index.html file, the script includes various dependencies and sets up System.js configuration. The app is bootstrapped using a boot.ts file.

However, upon running the app, Firefox throws an error stating that there was an exception during the instantiation of the Editor, specifically citing that the textarea is null. Any insights on how to resolve this issue would be greatly appreciated.

Sincerely, Web Developer

typescript angular codemirror

Answer 1

Answer №1

Many thanks for your assistance! I implemented some of the suggestions provided in your link and successfully utilized a directive to achieve my goal. Although I encountered some issues along the way, they were easily resolved once I realized that loading a link tag via a component was not feasible. For anyone facing a similar challenge, here is how I tackled it:

editor.component.ts

import {Component, ElementRef} from 'angular2/core'
import {EditorDirective} from './editor.directive'

@Component({
    selector: 'editor',
    template: `
    <textarea editor id="code" name="code">
        // Some content
    </textarea>
`,
    directives: [EditorDirective]
})


export class EditorComponent{
    constructor(){}
}

editor.directive.ts

import {Directive, ElementRef, Renderer} from 'angular2/core'

declare var CodeMirror: any;

@Directive({
    selector: '[editor]'
})

export class EditorDirective {
    editor: any;
    constructor(public element: ElementRef, public renderer: Renderer){
        this.editor = new CodeMirror.fromTextArea(element.nativeElement, {lineNumbers: true, mode: {name: "javascript", globalVars: true}});
    }
}

Lastly, index.html:

<html>
    <head>

    <title>Angular 2 and CodeMirror</title>

    <script src="node_modules/es6-shim/es6-shim.min.js"></script>
    <script src="node_modules/systemjs/dist/system-polyfills.js"></script>

    <script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
    <script src="node_modules/systemjs/dist/system.src.js"></script>
    <script src="node_modules/rxjs/bundles/Rx.js"></script>
    <script src="node_modules/angular2/bundles/angular2.dev.js"></script>
    <script src="node_modules/angular2/bundles/http.dev.js"></script>
    <script src="node_modules/angular2/bundles/router.dev.js"></script>
    <script src="codemirror-5.14.2/lib/codemirror.js"></script>
    <script src="codemirror-5.14.2/addon/hint/show-hint.js"></script>
    <script src="codemirror-5.14.2/addon/hint/javascript-hint.js"></script>
    <script src="codemirror-5.14.2/mode/javascript/javascript.js"></script>
    <script src="codemirror-5.14.2/mode/markdown/markdown.js"></script>

    <link rel=stylesheet href="codemirror-5.14.2/doc/docs.css">
    <link rel="stylesheet" href="codemirror-5.14.2/lib/codemirror.css">
    <link rel="stylesheet" href="codemirror-5.14.2/addon/hint/show-hint.css">

    <script>
        System.config({
            packages: {        
                meang2app: {
                format: 'register',
                defaultExtension: 'js'
                }
            }
        });
      System.import('meang2app/dist/editor.component')
          .then(null, console.error.bind(console));
    </script>

    </head>

  <body>
      <app>Loading</app>
  </body>

</html>

Answer 2

Many thanks for your assistance! I implemented some of the suggestions provided in your link and successfully utilized a directive to achieve my goal. Although I encountered some issues along the way, they were easily resolved once I realized that loading a link tag via a component was not feasible. For anyone facing a similar challenge, here is how I tackled it:

editor.component.ts

import {Component, ElementRef} from 'angular2/core'
import {EditorDirective} from './editor.directive'

@Component({
    selector: 'editor',
    template: `
    <textarea editor id="code" name="code">
        // Some content
    </textarea>
`,
    directives: [EditorDirective]
})


export class EditorComponent{
    constructor(){}
}

editor.directive.ts

import {Directive, ElementRef, Renderer} from 'angular2/core'

declare var CodeMirror: any;

@Directive({
    selector: '[editor]'
})

export class EditorDirective {
    editor: any;
    constructor(public element: ElementRef, public renderer: Renderer){
        this.editor = new CodeMirror.fromTextArea(element.nativeElement, {lineNumbers: true, mode: {name: "javascript", globalVars: true}});
    }
}

Lastly, index.html:

<html>
    <head>

    <title>Angular 2 and CodeMirror</title>

    <script src="node_modules/es6-shim/es6-shim.min.js"></script>
    <script src="node_modules/systemjs/dist/system-polyfills.js"></script>

    <script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
    <script src="node_modules/systemjs/dist/system.src.js"></script>
    <script src="node_modules/rxjs/bundles/Rx.js"></script>
    <script src="node_modules/angular2/bundles/angular2.dev.js"></script>
    <script src="node_modules/angular2/bundles/http.dev.js"></script>
    <script src="node_modules/angular2/bundles/router.dev.js"></script>
    <script src="codemirror-5.14.2/lib/codemirror.js"></script>
    <script src="codemirror-5.14.2/addon/hint/show-hint.js"></script>
    <script src="codemirror-5.14.2/addon/hint/javascript-hint.js"></script>
    <script src="codemirror-5.14.2/mode/javascript/javascript.js"></script>
    <script src="codemirror-5.14.2/mode/markdown/markdown.js"></script>

    <link rel=stylesheet href="codemirror-5.14.2/doc/docs.css">
    <link rel="stylesheet" href="codemirror-5.14.2/lib/codemirror.css">
    <link rel="stylesheet" href="codemirror-5.14.2/addon/hint/show-hint.css">

    <script>
        System.config({
            packages: {        
                meang2app: {
                format: 'register',
                defaultExtension: 'js'
                }
            }
        });
      System.import('meang2app/dist/editor.component')
          .then(null, console.error.bind(console));
    </script>

    </head>

  <body>
      <app>Loading</app>
  </body>

</html>

Answer 3

Answer №2

Avoid using ElementRef in your Angular 2 application, as suggested by the official documentation. It is important to steer clear of:

creating tight connections between your app and rendering layers, which can hinder the separation of these elements and restrict deployment in a web worker environment.

Instead, opt for Renderer2:

editor.directive.ts

@Directive({
  selector: '[editor]'
})
export default class EditorDirective {
  editor: any;

  constructor(private _renderer: Renderer) {}

  ngAfterViewInit() {
    this.editor = CodeMirror.fromTextArea(
      this._renderer.selectRootElement('[editor]'),
      {
        lineNumbers: true, 
        mode: {name: "javascript", globalVars: true}
      }
    );
  }
}

Answer 4

Avoid using ElementRef in your Angular 2 application, as suggested by the official documentation. It is important to steer clear of:

creating tight connections between your app and rendering layers, which can hinder the separation of these elements and restrict deployment in a web worker environment.

Instead, opt for Renderer2:

editor.directive.ts

@Directive({
  selector: '[editor]'
})
export default class EditorDirective {
  editor: any;

  constructor(private _renderer: Renderer) {}

  ngAfterViewInit() {
    this.editor = CodeMirror.fromTextArea(
      this._renderer.selectRootElement('[editor]'),
      {
        lineNumbers: true, 
        mode: {name: "javascript", globalVars: true}
      }
    );
  }
}

Answer 5

Answer №3

One option for integrating CodeMirror with Angular is using the wrapper called ngx-codemirror. You can find more information about it at https://github.com/scttcper/ngx-codemirror.

Answer 6

One option for integrating CodeMirror with Angular is using the wrapper called ngx-codemirror. You can find more information about it at https://github.com/scttcper/ngx-codemirror.

Answer 7

Answer №4

It seems like the issue may stem from not retrieving the correct DOM element using the BrowserDomAdapter. It appears that the adapter is searching for the textarea starting from the html root instead of within the current component context, resulting in a null value for the textbox.

To resolve this, consider various methods to access an element within the template and utilize it in your component code (such as when initializing codemirror): Angular2: What is the best way to get a reference of a template element

Answer 8

It seems like the issue may stem from not retrieving the correct DOM element using the BrowserDomAdapter. It appears that the adapter is searching for the textarea starting from the html root instead of within the current component context, resulting in a null value for the textbox.

To resolve this, consider various methods to access an element within the template and utilize it in your component code (such as when initializing codemirror): Angular2: What is the best way to get a reference of a template element

Incorporating CodeMirror into Angular2 using TypeScript

Answer №1

Answer №2

Answer №3

Answer №4

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