why it is not working with nodemon index.js while it is working with node index.js

Question

nodmon : The term 'nodmon' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At line:1 char:1

• nodmon index.js

•   + CategoryInfo          : ObjectNotFound: (nodmon:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException
  
  
  
  

app listening on port