Typicalc/frontend/src/mathjax-adapter.ts

import {LitElement, html} from 'lit-element';
import {TemplateResult} from "lit-html";

declare let window: {
	MathJax: {
		typesetShadow: (shadowRoot: ShadowRoot, callback: () => void) => void,
		isInitialized: boolean,
	};
	addEventListener: (event: string, listener: () => void) => void;
};

export abstract class MathjaxAdapter extends LitElement {
	private execTypeset(shadowRoot: ShadowRoot) {
		if (window.MathJax) {
			window.MathJax.typesetShadow(shadowRoot, () => this.calculateSteps());
		}
	}

	protected requestTypeset() {
		this.updateComplete.then(() => {
			if (window.MathJax === undefined || !window.MathJax.isInitialized) {
				window.addEventListener('mathjax-initialized', () => this.execTypeset(this.shadowRoot!));
			} else {
				this.execTypeset(this.shadowRoot!);
			}
		});
	}

	render(): TemplateResult {
		return html`<mjx-doc id="mjx-document"><mjx-head></mjx-head><mjx-body>
			<div id="tc-content"></div>
		</mjx-body></mjx-doc>`;
	}

	protected showStep(_n: number): void {
		/* ignore by default */
	}

	protected calculateSteps(): void {
	}
}