Add example test

babel.config.js

@@ -1,5 +1,5 @@
 module.exports = {
-    presets: ["@vue/cli-plugin-babel/preset"],
+    presets: ["@vue/cli-plugin-babel/preset", "@babel/preset-typescript"],
     plugins: [
         [
             "module:@jetblack/operator-overloading",

jest.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+    moduleDirectories: ["src", "node_modules"]
+};

package.json

@@ -6,11 +6,13 @@
     "start": "vue-cli-service serve",
     "serve": "vue-cli-service serve",
     "build": "vue-cli-service build",
-    "lint": "vue-cli-service lint"
+    "lint": "vue-cli-service lint",
+    "test": "jest"
   },
   "dependencies": {
     "@pixi/particle-emitter": "^5.0.4",
     "core-js": "^3.6.5",
+    "jest-environment-jsdom": "^28.1.1",
     "lodash.clonedeep": "^4.5.0",
     "lz-string": "^1.4.4",
     "nanoevents": "^6.0.2",
@@ -24,9 +26,13 @@
     "vuedraggable": "^4.1.0"
   },
   "devDependencies": {
+    "@babel/core": "^7.18.5",
+    "@babel/preset-env": "^7.18.2",
+    "@babel/preset-typescript": "^7.17.12",
     "@ivanv/vue-collapse-transition": "^1.0.2",
     "@jetblack/operator-overloading": "^0.2.0",
     "@rushstack/eslint-patch": "^1.1.0",
+    "@types/jest": "^28.1.3",
     "@types/lodash.clonedeep": "^4.5.6",
     "@types/lz-string": "^1.3.34",
     "@vue/babel-plugin-jsx": "^1.1.1",
@@ -38,12 +44,15 @@
     "@vue/eslint-config-prettier": "^7.0.0",
     "@vue/eslint-config-typescript": "^10.0.0",
     "babel-eslint": "^10.1.0",
+    "babel-jest": "^28.1.1",
     "eslint": "^8.6.0",
+    "jest": "^28.1.1",
     "lint-staged": "^12.3.4",
     "prettier": "^2.5.1",
     "raw-loader": "^4.0.2",
     "sass": "^1.48.0",
     "sass-loader": "^10.2.0",
+    "ts-jest": "^28.0.5",
     "tsconfig-paths-webpack-plugin": "^3.5.1",
     "typescript": "~4.5.5"
   },

tests/example.test.ts

@@ -0,0 +1,6 @@
+import Decimal from "util/bignum";
+
+test("Decimals?", () => {
+    const x = new Decimal(3);
+    expect(x.m).toBe(3);
+});

tsconfig.json

@@ -17,7 +17,8 @@
     "sourceMap": true,
     "baseUrl": "src",
     "types": [
-      "webpack-env"
+      "webpack-env",
+      "jest"
     ],
     "lib": [
       "esnext",