Fixing “unexpected token in JSON” error in Nodejs Javascript

Sep 2020, Gorakhpur, India

Error while parsing JSON

So, I was working on a project where I created an API that takes Users Location and Shops Location as a request parameter and returns the distance from the user under a certain diameter.

Here is the parameter I was sending as Body in Postman

shop = [ { latitude: 26.759362, longitude: 83.377485, name: “Dominoes” }, { latitude: 26.753586, longitude: 83.378468, name: “Rangrezza” }, { latitude: 26.752640, longitude: 83.370958, name: “Shahanshah” }, { latitude: 26.852785, longitude: 80.999626, name: “Royal Cafe” }, { latitude: 26.857992, longitude: 80.947613, name: “Mummas Cafe” }, { latitude: 28.672742, longitude: 77.452321, name: “Maharani Kitchen”}, { latitude: 28.677797, longitude: 77.442009, name: “Handi Dining”} ]

user = [{“key”:”user”,”value”:”{ latitude: 100, longitude: 100 }”,”description”:””,”type”:”text”,”enabled”:true}]

After testing everything through hardcoded values, the JSON that I was sending in Body as Form Data was not getting Parsed using JSON.parse nor getting converted using JSON.stringify.

I was always getting an error of “Unexpected token l in JSON at position 4”

After some research, I found the Really-Relaxed-JSON library.

• Commas are optional between objects pairs and array items.
• Trailing commas are allowed.
• Quotes are optional around simple keys and simple values.
• Single-quote pairs, double-quote pairs, and backtick pairs can be used for strings.
• Single-line and multi-line comments are allowed.
• Multiline strings are allowed.

Import Really Relaxed JSON as a constant using:

const parser = require('really-relaxed-json').createParser();

The following code parses the data mentioned above and gives this as a result:

The code prints:

1) The req.body received via postman.

2) The string that we get using Really Relaxed JSON.

3) The string parsed back to JSON to be used in the code.

This is how I was able to get this API up and running quickly.

This is a quick and hacky solution, not recommended for production but useful for learning.

I figured this out some years back when I was still intermediate in Node.js.