Implement plugin

src/utils.js

@@ -0,0 +1,33 @@
+export function renderEquation( equation, element, engine = 'katex', display = false ) {
+	if ( engine === 'mathjax' && typeof katex !== 'mathjax' ) {
+		if (display) {
+			element.innerHTML = '\\[' + equation + '\\]';
+		} else {
+			element.innerHTML = '\\(' + equation + '\\)';
+		}
+		/* eslint-disable */
+		MathJax.Hub.Queue( [ 'Typeset', MathJax.Hub, element ] );
+		/* eslint-enable */
+	}
+	else if ( engine === 'katex' && typeof katex !== 'undefined' ) {
+		/* eslint-disable */
+        katex.render( equation, element, {
+			throwOnError: false,
+			displayMode: display
+        } );
+        /* eslint-enable */
+	} else {
+		element.innerHTML = equation;
+		console.warn( 'math-tex-typesetting-missing: Missing the mathematical typesetting engine for tex.' );
+	}
+}
+
+export function getSelectedMathModelWidget( selection ) {
+	const selectedElement = selection.getSelectedElement();
+
+	if ( selectedElement && selectedElement.is( 'mathtex' ) ) {
+		return selectedElement;
+	}
+
+	return null;
+}