Build and Deploy Job failed after adding ESLint and Prettier to API

[phwt]

Describe the bug

I am trying to configure the API project built with TypeScript with ESLint and Prettier but after I add it the "Build and Deploy Job" is failed with this message:

The function language detected is unsupported or invalid. The following languages are valid: dotnet, dotnetisolated, node, python. If you are not using Azure Functions, you can skip this check by removing the 'api_location' input from the workflow file.

To Reproduce Here are the steps I've taken on setting up the ESLint and Prettier:

1. Install ESLint, Prettier, and its plugins

   npm i -D @typescript-eslint/eslint-plugin @typescript-eslint/parser eslint \
   eslint-config-airbnb-base eslint-config-airbnb-typescript \
   eslint-config-prettier eslint-plugin-import eslint-plugin-prettier prettier

2. Run eslint --init to generate .eslintrc.js

Difference in project files

.eslintrc.js

+ module.exports = {
+     "env": {
+         "es2021": true,
+         "node": true
+     },
+     "parser": "@typescript-eslint/parser",
+     "parserOptions": {
+         "ecmaVersion": 12,
+         "sourceType": "module"
+     },
+     "plugins": [
+         "@typescript-eslint"
+     ],
+     "rules": {
+     }
+ };

package.json

      "start:host": "func start",
      "start": "npm-run-all --parallel start:host watch",
      "test": "jest",
-     "generate-spec": "tsoa spec"
+     "generate-spec": "tsoa spec",
+     "lint": "eslint .",
+     "format": "prettier --write './**/*.{js,ts,css,md,json}' --config ./.prettierrc"
  },
  "description": "",
  "devDependencies": {
  @@ -20,9 +22,18 @@
      "@babel/preset-typescript": "^7.15.0",
      "@types/jest": "^27.0.2",
      "@types/node": "^16.11.3",
+     "@typescript-eslint/eslint-plugin": "^5.3.1",
+     "@typescript-eslint/parser": "^5.3.1",
      "babel-jest": "^27.3.1",
+     "eslint": "^7.32.0",
+     "eslint-config-airbnb-base": "^14.2.1",
+     "eslint-config-airbnb-typescript": "^15.0.0",
+     "eslint-config-prettier": "^8.3.0",
+     "eslint-plugin-import": "^2.25.2",
+     "eslint-plugin-prettier": "^4.0.0",
      "jest": "^27.2.4",
      "npm-run-all": "^4.1.5",
+     "prettier": "^2.4.1",
      "ts-jest": "^27.0.5",
      "typescript": "^4.4.4"
  },

Expected behavior

• ESLint and Prettier can help me lint, format, and enforce code styles
• "Build and Deploy Job" can run and deploy without any errors.

Additional context

• API project is generated with func new
• I've run eslint . before triggering the job to ensure that the error does not relate to the code styles
• In the reproducing part - I've installed many plugins along with the eslint and prettier but the reason I'm not using them in the .eslintrc.js is also to ensure that the error does not relate to the code styles (enforced by the plugins)

[dombarnes]

What does your build script in package.json do?

[phwt]

What does your build script in package.json do?

It generates an OpenAPI specification with tsoa and then starts compilation with tsc

"build": "npm run generate-spec && tsc",
"generate-spec": "tsoa spec"

Here's the rest of the "package.json" file

```json { "name": "api", "version": "1.0.0", "scripts": { "build": "npm run generate-spec && tsc", "build:production": "npm run prestart && npm prune --production", "watch": "tsc --w", "prestart": "npm run build && func extensions install", "start:host": "func start", "start": "npm-run-all --parallel start:host watch", "test": "jest", "generate-spec": "tsoa spec", "lint": "eslint .", "format": "prettier --write './**/*.{js,ts,css,md,json}' --config ./.prettierrc" }, "description": "", "devDependencies": { "@azure/functions": "^1.0.1-beta1", "@babel/core": "^7.15.8", "@babel/plugin-proposal-decorators": "^7.15.4", "@babel/preset-env": "^7.15.8", "@babel/preset-typescript": "^7.15.0", "@types/jest": "^27.0.2", "@types/node": "^16.11.3", "@typescript-eslint/eslint-plugin": "^5.3.1", "@typescript-eslint/parser": "^5.3.1", "babel-jest": "^27.3.1", "eslint": "^7.32.0", "eslint-config-airbnb-base": "^14.2.1", "eslint-config-airbnb-typescript": "^15.0.0", "eslint-config-prettier": "^8.3.0", "eslint-plugin-import": "^2.25.2", "eslint-plugin-prettier": "^4.0.0", "jest": "^27.2.4", "npm-run-all": "^4.1.5", "prettier": "^2.4.1", "ts-jest": "^27.0.5", "typescript": "^4.4.4" }, "dependencies": { "@typegoose/typegoose": "^9.0.1", "babel-plugin-transform-typescript-metadata": "^0.3.2", "dayjs": "^1.10.7", "mongoose": "^6.0.8", "tsoa": "^3.13.0" } } ```