npm install cannot read package.json

Question

I am trying to manage my node package dependencies. I'd like to be able to install all the required dependencies by running a command, and from what I have read, one way to achieve this is using a package.json file and running npm install. So my JSON file looks like this:

{
 "name": "Name-Of-The-Thing",
 "description": "The Thing's Name",
 "author": "The Dude <[email protected]>",
 "dependencies": {
      "mocha":">= 1.12.0",
      "mocha-phantomjs":">= 3.1.0",
      "chai":">= 1.7.2",
      "phantomjs":">= 1.9.1"
 }
}

However npm install reports the following error:

npm ERR! Failed to parse json
npm ERR! Unexpected token ?
npm ERR! File: C:\Path\To\The\Thing\package.json
npm ERR! Failed to parse package.json data.
npm ERR! package.json must be actual JSON, not just JavaScript.
npm ERR!
npm ERR! This is not a bug in npm.
npm ERR! Tell the package author to fix their package.json file. JSON.parse

npm ERR! System Windows_NT 6.2.9200
npm ERR! command "C:\\Program Files\\nodejs\\\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "test"
npm ERR! cwd C:\Path\To\The\Thing
npm ERR! node -v v0.8.15
npm ERR! npm -v 1.1.66
npm ERR! file C:\Path\To\The\Thing\package.json
npm ERR! code EJSONPARSE
npm ERR!
npm ERR! Additional logging details can be found in:
npm ERR!     C:\Path\To\The\Thing\npm-debug.log
npm ERR! not ok code 0

Anyone know why?

Answer 1

Proper answer:

Your editor adds a byte-order-mark to the JSON file, which makes the octet-stream an invalid JSON text.

JSON RFC says:

JSON text SHALL be encoded in Unicode. The default encoding is UTF-8.

Since the first two characters of a JSON text will always be ASCII characters [RFC0020], it is possible to determine whether an octet stream is UTF-8, UTF-16 (BE or LE), or UTF-32 (BE or LE) by looking at the pattern of nulls in the first four octets.

       00 00 00 xx  UTF-32BE

       00 xx 00 xx  UTF-16BE
       xx 00 00 00  UTF-32LE
       xx 00 xx 00  UTF-16LE
       xx xx xx xx  UTF-8

The bug report you mentioned has been closed for this reason.

From my understanding, any valid ASCII encoded text also happens to be valid UTF-8, so together with the absence of the BOM it explains why it now works as expected.

In general, I think you should set up your text editor to save files in UTF-8, without a byte-order-mark. See What's the difference between UTF-8 and UTF-8 without BOM? for discussion. Per What encoding is expected for Node.js source code? , Node.js would accept non-ASCII characters in JS source files encoded this way. This can be handy when you want to embed a non-ASCII string somewhere in the source code.

Answer 2

npm ERR! Unexpected token ?

In case there is no BOM, also check if you just have a "?" somewhere in the file or other errors, e.g. a missing or additional ",".