add code coverage but it doesn't work all the way yet

getting this error when trying to view the html report for some files: istanbuljs/istanbuljs#322

.babelrc

@@ -0,0 +1,4 @@
+{
+  "presets": ["next/babel"],
+  "plugins": ["istanbul"]
+}

.gitignore

@@ -14,3 +14,6 @@ cypress/videos
 cypress/screenshots
 
 *.tsbuildinfo
+
+coverage
+.nyc_output

cypress.json

@@ -1,4 +1,9 @@
 {
   "nodeVersion": "system",
-  "baseUrl": "http://localhost:4000/"
+  "baseUrl": "http://localhost:4000/",
+  "env": {
+    "codeCoverage": {
+      "url": "/api/__coverage__"
+    }
+  }
 }

cypress/plugins/index.ts

@@ -11,6 +11,10 @@ const pluginConfig: Cypress.PluginConfig = (on, config) => {
       },
     }),
   )
+
+  require("@cypress/code-coverage/task")(on, config)
+
+  return config
 }
 
 export = pluginConfig

cypress/support/index.ts

@@ -1,3 +1,4 @@
+import "@cypress/code-coverage/support"
 import "@testing-library/cypress/add-commands"
 
 before(() => {

package.json

@@ -2,12 +2,13 @@
   "name": "thoughtbucket",
   "private": true,
   "scripts": {
+    "clean": "trash .next coverage .nyc_output",
     "dev": "next dev",
-    "dev-test": "trash .next && dotenv -e .env.test -- concurrently --kill-others npm:dev npm:cypress-open",
+    "dev-test": "npm run clean && dotenv -e .env.test -- concurrently --kill-others npm:dev npm:cypress-open",
     "test-dev": "npm run dev-test",
     "build": "next build",
     "start": "next start",
-    "test": "dotenv -e .env.test -- ts-node --transpile-only ./scripts/test.ts",
+    "test": "npm run clean && dotenv -e .env.test -- ts-node --transpile-only ./scripts/test.ts",
     "typecheck": "tsc --noEmit",
     "lint": "eslint --ext js,ts,tsx .",
     "format": "prettier --write .",
@@ -40,6 +41,8 @@
     "zod": "3.9.1"
   },
   "devDependencies": {
+    "@cypress/code-coverage": "3.9.11",
+    "@istanbuljs/nyc-config-typescript": "1.0.1",
     "@itsmapleleaf/configs": "1.0.0",
     "@next/eslint-plugin-next": "11.1.2",
     "@tailwindcss/line-clamp": "0.2.1",
@@ -53,6 +56,7 @@
     "@typescript-eslint/eslint-plugin": "4.31.2",
     "@typescript-eslint/parser": "4.31.2",
     "autoprefixer": "10.3.6",
+    "babel-plugin-istanbul": "6.0.0",
     "concurrently": "6.2.1",
     "cypress": "8.4.1",
     "cypress-esbuild-preprocessor": "1.0.2",
@@ -99,5 +103,25 @@
         }
       }
     ]
+  },
+  "nyc": {
+    "extension": [
+      ".js",
+      ".jsx",
+      ".ts",
+      ".tsx"
+    ],
+    "extends": "@istanbuljs/nyc-config-typescript",
+    "include": [
+      "src/**/*"
+    ],
+    "exclude": [
+      "src/pages/api/__coverage__.js"
+    ],
+    "sourceMap": true,
+    "instrument": true,
+    "reporter": [
+      "html"
+    ]
   }
 }