Why isn't my package.json updated by npm install?

Question

I'm just starting out with npm, and as far as I understand the npm install command should automatically update the package.json file, but with me it unfortunately doesn't.

I'm on OSX and in a new dir called npmtest I did the following:

$ ls  # let's first confirm the folder is empty
$
$ npm init --y
Wrote to /Users/kramer65/Downloads/npmtest/package.json:

{
  "name": "npmtest",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

I then installed underscore:

$ npm install underscore
npmtest@1.0.0 /Users/kramer65/Downloads/npmtest
└── underscore@1.8.3

npm WARN npmtest@1.0.0 No description
npm WARN npmtest@1.0.0 No repository field.

which seems to be installed fine:

$ ls -l
total 8
drwxr-xr-x  3 kramer65  staff  102 Oct 18 17:47 node_modules
-rw-r--r--  1 kramer65  staff  221 Oct 18 17:47 package.json

unfortunately npm list complains that it's not in the package.json file with the extraneous flag:

$ npm list
npmtest@1.0.0 /Users/kramer65/Downloads/npmtest
└── underscore@1.8.3 extraneous

npm ERR! extraneous: underscore@1.8.3 /Users/kramer65/Downloads/npmtest/node_modules/underscore

Which I can confirm:

$ cat package.json
{
  "name": "npmtest",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

The question is; why isn't it entered in the package.json file? Shouldn't that go automatically? What am I doing wrong here? All tips are welcome!

Answer 1

npm install doesn't update the package.json file, npm install *module name* --save updates the json package. Hope that helps.