How to fix this frequent 'Failed to parse json' problem with npm?

Question

I have a frequent problem with npm, it occurs when running npm start command in a react project folder after some time not working with that project.

I get several lines of log include 'Failed to parse json' and 'package.json must be actual JSON, not just Javascript'.

The problem always happen after i get to deal with the project after some weeks of no-use, my package.json file seems fine and this is an example

{
  "name": "carzyGame",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "react": "^16.4.2",
    "react-dom": "^16.4.2",
    "react-scripts": "1.1.4",
    "redux": "^4.0.0",
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
  }
}

another one:

{
  "name": "neighborhood",
  "version": "0.1.0",
  "private": true,
  "predeploy": "npm run build",
  "deploy": "gh-pages -d build" 
  "dependencies": {
    "escape-string-regexp": "^1.0.5",
    "react": "^16.4.1",
    "react-dom": "^16.4.1",
    "react-foursquare": "^1.0.3",
    "react-scripts": "1.1.4",
    "sort-by": "^1.2.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  }
}

I tried to uninstall npm by npm uninstall and i got the same error, also removing node modules file could not help (the purpose is to re-install it).

So what is the reason of that problem and how to solve it?

S M · Accepted Answer · 2018-11-07 23:31:29Z

1

The faulty lines are:

    "redux": "^4.0.0",

    "eject": "react-scripts eject",

Unlike in JavaScript, a trailing comma is not allowed in the last key-value pair of a JSON object.

answered Nov 7, 2018 at 23:31

S M

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3 Comments

Saher Elgendy Over a year ago

Thank you, i have edited the post with another project package.json file content, it does not contain the trailing comma and still returns the same error??

S M Over a year ago

You missed the comma after "deploy": "gh-pages -d build".

S M Over a year ago

I would recommend using a JSON validator to diagnose these errors. I use stedolan.github.io/jq - when I pasted your JSON into it I got the error "parse error: Expected separator between values at line 7, column 16" which is pretty explicit about what the problem is.

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