refactor: Refactor and add a test

src/element/subtypes/global.d.ts

@@ -1,6 +0,0 @@
-declare module "mathjax-full/js/input/asciimath/mathjax2/legacy/MathJax";
-
-declare module SREfeature {
-  function custom(locale: string): Promise<string>;
-  export = custom;
-}

src/element/subtypes/mathjax/index.ts

@@ -4,6 +4,12 @@ import { addSubtypeMethods } from "../";
 import { getMathSubtypeRecord } from "./types";
 import { prepareMathSubtype } from "./implementation";
 
+declare global {
+  module SREfeature {
+    function custom(locale: string): Promise<string>;
+  }
+}
+
 export const MathJaxSubtype = "mathjax";
 
 // The main hook to use the MathJax subtype

src/element/subtypes/mathjax/tests/implementation.test.tsx

@@ -1,14 +1,20 @@
+import { vi } from "vitest";
 import { render } from "../../../../tests/test-utils";
 import { API } from "../../../../tests/helpers/api";
 import { Excalidraw } from "../../../../packages/excalidraw/index";
 
 import { measureTextElement } from "../../../textElement";
 import { ensureSubtypesLoaded } from "../../";
+import { getMathSubtypeRecord } from "../types";
+import { prepareMathSubtype } from "../implementation";
 
-describe("mathjax", () => {
+describe("mathjax loaded", () => {
-  it("text-only measurements match", async () => {
+  beforeEach(async () => {
     await render(<Excalidraw />);
+    API.addSubtype(getMathSubtypeRecord(), prepareMathSubtype);
     await ensureSubtypesLoaded(["math"]);
+  });
+  it("text-only measurements match", async () => {
     const text = "A quick brown fox jumps over the lazy dog.";
     const elements = [
       API.createElement({ type: "text", id: "A", text, subtype: "math" }),
@@ -19,8 +25,6 @@ describe("mathjax", () => {
     expect(metrics1).toStrictEqual(metrics2);
   });
   it("minimum height remains", async () => {
-    await render(<Excalidraw />);
-    await ensureSubtypesLoaded(["math"]);
     const elements = [
       API.createElement({ type: "text", id: "A", text: "a" }),
       API.createElement({
@@ -44,4 +48,30 @@ describe("mathjax", () => {
     expect(height).toEqual(height1);
     expect(height).toEqual(height2);
   });
+  it("converts math to svgs", async () => {
+    const svgDim = 42;
+    vi.spyOn(SVGElement.prototype, "getBoundingClientRect").mockImplementation(
+      () => new DOMRect(0, 0, svgDim, svgDim),
+    );
+    const elements = [];
+    const type = "text";
+    const subtype = "math";
+    let text = "Math ";
+    elements.push(API.createElement({ type, text }));
+    text = "Math \\(\\alpha\\)";
+    elements.push(
+      API.createElement({ type, subtype, text, customData: { useTex: true } }),
+    );
+    text = "Math `beta`";
+    elements.push(
+      API.createElement({ type, subtype, text, customData: { useTex: false } }),
+    );
+    const metrics = {
+      width: measureTextElement(elements[0]).width + svgDim,
+      height: svgDim,
+      baseline: 0,
+    };
+    expect(measureTextElement(elements[1])).toStrictEqual(metrics);
+    expect(measureTextElement(elements[2])).toStrictEqual(metrics);
+  });
 });

src/element/subtypes/use.ts

@@ -1,3 +1,4 @@
+import { Subtype } from ".";
 import { ExcalidrawImperativeAPI } from "../../types";
 import {
   MathJaxSubtype,
@@ -5,13 +6,13 @@ import {
   useMathJaxSubtype,
 } from "./mathjax";
 
-const validSubtypes: readonly string[] = [MathJaxSubtype];
+const validSubtypes: readonly Subtype[] = [MathJaxSubtype];
-const subtypesUsed: string[] = [];
+const subtypesUsed: Subtype[] = [];
 
 // The main invocation hook for use in the UI
 export const useSubtypes = (
   api: ExcalidrawImperativeAPI | null,
-  subtypes?: string[],
+  subtypes?: Subtype[],
 ) => {
   selectSubtypesToEnable(subtypes);
   useMathJaxSubtype(api);
@@ -19,8 +20,8 @@ export const useSubtypes = (
 };
 
 // This MUST be called before the `useSubtype` calls.
-const selectSubtypesToEnable = (subtypes?: string[]) => {
+const selectSubtypesToEnable = (subtypes?: Subtype[]) => {
-  const subtypeList: string[] = [];
+  const subtypeList: Subtype[] = [];
   if (subtypes === undefined) {
     subtypeList.push(...validSubtypes);
   } else {

src/global.d.ts

@@ -116,3 +116,5 @@ declare namespace jest {
     toBeNonNaNNumber(): void;
   }
 }
+
+declare module "mathjax-full/js/input/asciimath/mathjax2/legacy/MathJax";

src/tests/subtypes.test.tsx

@@ -1,3 +1,4 @@
+import { vi } from "vitest";
 import fallbackLangData from "./helpers/locales/en.json";
 import {
   SubtypeLoadedCb,
@@ -458,9 +459,9 @@ describe("subtypes", () => {
       return { width: 1, height: 0, baseline: 0 };
     };
 
-    jest
+    vi.spyOn(textElementUtils, "measureText").mockImplementation(
-      .spyOn(textElementUtils, "measureText")
+      mockMeasureText,
-      .mockImplementation(mockMeasureText);
+    );
 
     elements.forEach((el) => {
       if (isTextElement(el)) {