have npm report the error with a package.json

[Pomax]

since npm relies on a well formatted package.json file, it would be nice if it could report the actual error it sees when trying to parse a bad package.json rather than merely reporting that there is some error without saying which line/column or the type of error encountered. If there is a JSON parse error perhaps the package.json file could be thrown at jshint to get the precise error?

[domenic]

I don't believe any JSON parsers expose this information, and we just use JSON.parse, which definitely doesn't. JSHint is not a JSON parser.

[Pomax]

I know, I'm not saying to use jshint instead of JSON parsing, but that it would be very helpful if, after a JSON.parse throws its parse error, that error is handled by running the package.json file that we now know has errors through a JS linter, which unlike JSON.parse will find the error tied to a location in the file and an error case number, which can then be reported as additional information. e.g.:

try {
  var package = require("./package.json");
  ...
}
catch (e) { 
  // alright, error in package.json. But what's the error?
  require("somelintinglibrary").lint("./package.json", function(err, result) {
    // we already know it's going to error out
    console.log("error in package.json: " + err.message + " (" + err.code + ")");
  });
}

or some such. Once you know that package.json is guaranteed to have an error it can be run through a linter to find the exact location and nature of the error, so that the user can find out what's wrong much faster than they currently can.

[domenic]

Yeah, I got that. But do you know of any JSON parsers that include line numbers in their error messages? JSHint isn't a JSON parser, so that won't work. (E.g. if your syntax error is forgetting quotes, JSHint will be fine with that.)

[Pomax]

Hmm, what about https://github.com/zaach/jsonlint ?

[domenic]

Could work. Would be helpful to run some tests on different invalid inputs and see what it gives you.

[adius]

+1

[ilanbiala]

Any progress on this? Seems like something so simple but so important when all that is usually missing is a comma or something visually insignificant.

[othiym23]

Yes! There has been! @smikes has done is all a huge favor!

Closed by abdd040. This is included in npm@2.7.1, which is the version currently being tested (npm@next).