CODE EXAMPLE FOR JAVASCRIPT

npm ERR! code ELIFECYCLE npm ERR! errno 2 npm ERR! functions@ lint: `tslint --project tsconfig.json`

Change the "firebase.json" file's "predeploy" section from this: 

 "functions": {
    "predeploy": [
      "npm --prefix "$RESOURCE_DIR" run lint",
      "npm --prefix "$RESOURCE_DIR" run build"
    ]
  },
  
To this:

 "functions": {
    "predeploy": [
      "npm --prefix "%RESOURCE_DIR%" run lint",
      "npm --prefix "%RESOURCE_DIR%" run build"
    ]
  }