Embeddable CM Markdown Editor

embeddable-editor.ts

/**
 * All credits go to mgmeyers for figuring out how to grab the proper editor prototype
 * 	 and making it easily deployable
 * Changes made to the original code:
 * 	 - Refactored to JS-only syntax (original code made use of React)
 * 	 - Added blur completion
 * 	 - Added some comments on how the code functions
 * 	 - Made editor settings fully optional
 * 	 - Allow all editor commands to function on this editor
 * 	 - Added typings for the editor(s) (will be added to obsidian-typings)
 * Make sure to also check out the original source code here: https://github.com/mgmeyers/obsidian-kanban/blob/main/src/components/Editor/MarkdownEditor.tsx
 */

import {
	App, Constructor, Keymap, Scope, ScrollableMarkdownEditor,
	TFile, WidgetEditorView, WorkspaceLeaf,
} from "obsidian";

import {EditorSelection, Extension, Prec} from "@codemirror/state";
import {EditorView, keymap, placeholder, ViewUpdate} from "@codemirror/view";

import {around} from "monkey-around";


function resolveEditorPrototype(app: App) {
	// Create a temporary editor to resolve the prototype of ScrollableMarkdownEditor
	const widgetEditorView = app.embedRegistry.embedByExtension.md(
		{ app, containerEl: document.createElement('div') },
		null as unknown as TFile,
		'',
	) as WidgetEditorView;

	// Mark as editable to instantiate the editor
	widgetEditorView.editable = true;
	widgetEditorView.showEditor();
	const MarkdownEditor = Object.getPrototypeOf(Object.getPrototypeOf(widgetEditorView.editMode!));

	// Unload to remove the temporary editor
	widgetEditorView.unload();

	return MarkdownEditor.constructor as Constructor<ScrollableMarkdownEditor>;
}

interface MarkdownEditorProps {
	cursorLocation?: { anchor: number, head: number };
	value?: string;
	cls?: string;
	placeholder?: string;

	onEnter: (editor: EmbeddableMarkdownEditor, mod: boolean, shift: boolean) => boolean;
	onEscape: (editor: EmbeddableMarkdownEditor) => void;
	onSubmit: (editor: EmbeddableMarkdownEditor) => void;
	onBlur: (editor: EmbeddableMarkdownEditor) => void;
	onPaste: (e: ClipboardEvent, editor: EmbeddableMarkdownEditor) => void;
	onChange: (update: ViewUpdate) => void;
}

const defaultProperties: MarkdownEditorProps = {
	cursorLocation: { anchor: 0, head: 0 },
	value: '',
	cls: '',
	placeholder: '',

	onEnter: () => false,
	onEscape: () => {},
	onSubmit: () => {},
	// NOTE: Blur takes precedence over Escape (this can be changed)
	onBlur: () => {},
	onPaste: () => {},
	onChange: () => {},
}


export class EmbeddableMarkdownEditor extends resolveEditorPrototype(app) implements ScrollableMarkdownEditor {
	options: MarkdownEditorProps;
	initial_value: string;
	scope: Scope;

	/**
	 * Construct the editor
	 * @remark Takes 5ms to fully construct and attach
	 * @param app - Reference to App instance
	 * @param container - Container element to add the editor to
	 * @param options - Options for controling the initial state of the editor
	 */
	constructor(app: App, container: HTMLElement, options: Partial<MarkdownEditorProps>) {
		super(app, container, {
			app,
			// This mocks the MarkdownView functions, which is required for proper functioning of scrolling
			onMarkdownScroll: () => {},
			getMode: () => 'source',
		});
		this.options = {...defaultProperties, ...options};
		this.initial_value = this.options.value!;
		this.scope = new Scope(this.app.scope);
		// NOTE: Hotkeys take precedence over CM keymap, so scope is introduced to allow for specific hotkeys to be overwritten
		//   In this case, since Mod+Enter is linked to the "Open link in new leaf" command, but it is also the default user action for submitting the editor,
		//      the scope is used to prevent the hotkey from executing (by returning `true`)
		// TODO: It is also possible to allow both behaviours to coexist:
		//     1) Fetch the command via hotkeyManager
		//     2) Execute the command callback
		//     3) Return the result of the callback (callback returns false if callback could not execute)
		//     		(In this case, if cursor is not on a link token, the callback will return false, and onEnter will be applied)
		this.scope.register(["Mod"], "Enter", (e, ctx) => {
			return true;
		});

		// Since the commands expect that this is a MarkdownView (with editMode as the Editor itself),
		//   we need to mock this by setting both the editMode and editor to this instance and its containing view respectively
		// @ts-expect-error (editMode is normally a MarkdownSubView)
		this.owner.editMode = this;
		this.owner.editor = this.editor;

		this.set(options.value || '');
		this.register(
			around(this.app.workspace, {
				// @ts-expect-error (Incorrectly matches the deprecated setActiveLeaf method)
				setActiveLeaf: (oldMethod: (leaf: WorkspaceLeaf, params?: ({ focus?: boolean })) => void) =>
					(leaf: WorkspaceLeaf, params: { focus?: boolean }) => {
						// If the editor is currently focused, prevent the workspace setting the focus to a workspaceLeaf instead
						if (!this.activeCM.hasFocus)
							oldMethod.call(this.app.workspace, leaf, params);
					},
			}),
		);

		// Execute onBlur when the editor loses focus
		// NOTE: Apparently Chrome does a weird thing where removing an element from the DOM triggers a blur event
		//		 (Hence why the ._loaded check is necessary)
		if (this.options.onBlur !== defaultProperties.onBlur) {
			this.editor.cm.contentDOM.addEventListener('blur', () => {
				this.app.keymap.popScope(this.scope);
				if (this._loaded)
					this.options.onBlur(this)
			});
		}

		// Whenever the editor is focused, set the activeEditor to the mocked view (this.owner)
		// This allows for the editorCommands to actually work
		this.editor.cm.contentDOM.addEventListener('focusin', (e) => {
			this.app.keymap.pushScope(this.scope);
			this.app.workspace.activeEditor = this.owner;
		});

		if (options.cls) this.editorEl.classList.add(options.cls);
		if (options.cursorLocation) {
			this.editor.cm.dispatch({
				selection: EditorSelection.range(options.cursorLocation.anchor, options.cursorLocation.head),
			});
		}
	}

	get value() {
		return this.editor.cm.state.doc.toString();
	}

	onUpdate(update: ViewUpdate, changed: boolean) {
		super.onUpdate(update, changed);
		if (changed) this.options.onChange(update);
	}

	/**
	 * Loads the CM extensions for rendering Markdown and handling user inputs
	 * Note that other plugins will not be able to send updates to these extensions to change configurations
	 */
	buildLocalExtensions(): Extension[] {
		const extensions = super.buildLocalExtensions();
		if (this.options.placeholder) extensions.push(placeholder(this.options.placeholder));

		/* Editor extension for handling specific user inputs */
		extensions.push(EditorView.domEventHandlers({ paste: (event) => {
			this.options.onPaste(event, this);
		}}));
		extensions.push(Prec.highest(keymap.of([
			{
				key: 'Enter',
				run: (cm) => this.options.onEnter(this, false, false),
				shift: (cm) => this.options.onEnter(this, false, true)
			},
			{
				key: 'Mod-Enter',
				run: (cm) => this.options.onEnter(this, true, false),
				shift: (cm) => this.options.onEnter(this, true, true)
			},
			{
				key: 'Escape',
				run: (cm) => {
					this.options.onEscape(this);
					return true;
				},
				preventDefault: true
			}
		])));

		/* Additional Editor extensions (renderers, ...) */


		return extensions;
	}

	/**
	 * Ensure that the editor is properly destroyed when the view is closed
	 */
	destroy(): void {
		if (this._loaded)
			this.unload();
		this.app.keymap.popScope(this.scope);
		this.app.workspace.activeEditor = null;
		this.containerEl.empty();
		super.destroy();
	}

	/**
	 * When removing as a component, destroy will also get invoked
	 */
	onunload() {
		super.onunload();
		this.destroy();
	}
}

LICENSE

Copyright 2024 Matthew Meyers, Fevol

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

view.ts

/**
 * This view provides an example on how you can utilise the EmbeddableMarkdownEditor
 * Note that it is not required for the editor be marked to a leaf or view,
 *   but you do need to be careful in managing the editor lifecycle (via registering it to a component or destroying it manually) 
 */

import {EmbeddableMarkdownEditor} from "./embeddable-editor";
import SamplePlugin from "./main";
import {ItemView, Notice, WorkspaceLeaf} from "obsidian";

export const SAMPLE_VIEW_ID = "example-view";
export class SampleView extends ItemView {
	editors: HTMLElement[] = [];

	constructor(private plugin: SamplePlugin, leaf: WorkspaceLeaf) {
		super(leaf);
	}

	getViewType() {
		return SAMPLE_VIEW_ID;
	}

	getDisplayText() {
		return "Sample View";
	}

	createEditor(container: HTMLElement) {
		// The editor can easily be destructed via calling the.removeChild(editor) method (if registered),
		//    or by calling editor.destroy()
		return this.addChild(new EmbeddableMarkdownEditor(this.app, container, {
			onEscape: (editor) => {
				new Notice(`Escaped the editor: (${editor.initial_value})`);
				this.removeChild(editor);
			},
			onEnter: (editor, mod: boolean, shift: boolean) => {
				if (mod) {
					new Notice(`Ctrl+Entered on the editor: (${editor.value})`);
					this.removeChild(editor);
				}
				return false;
			},
			onSubmit: (editor) => {
				new Notice(`Submitted on the editor: (${editor.value})`);
				this.removeChild(editor);
			},
			// onBlur: (editor) => {
			// 	new Notice(`Unfocused the editor: (${editor.initial_value})`);
			// 	this.removeChild(editor);
			// },
			value: "Interesting text\n[Some link](https://www.google.com/)",
		}));
	}

	async onOpen() {
		const container = this.containerEl.children[1] as HTMLElement;
		container.empty();

		container.style.display = 'flex';
		container.style.flexDirection = 'column';
		container.style.gap = '1%';


		const numEditors = 3;
		for (let i = 0; i < numEditors; i++) {
			const editorContainer = container.createDiv({ cls: 'sample-editor' });
			editorContainer.style.height = Math.floor((100 - numEditors) / numEditors) + "%";
			editorContainer.style.border = "1px solid var(--background-modifier-border)";

			this.editors.push(editorContainer);
			this.createEditor(editorContainer);
		}
	}
}

LICENSE DISCLAIMER: Original source code of Kanban is GPLv3, explicit permission was given for sharing the editor construction code under MIT.