fixJSON function. Removes comments and trailing commas from JSON

index.js

/**
 * Removes comments and trailing commas from JSON
 */
function fixJSON(str) {
  return str
    // remove comments
    .replace(/\/(?:\*{2,}\s[\s\S]+?|\*[^\*]+?)\*\/|([\s;])+\/\/.*$/gm, '')
    // remove trailing commas
    .replace(/,+\s*(\}|\])/g, '$1');
}

var json_demo = `
{
  /**
   * This comment will be removed
   */
  "foo": 1,
  
  // this one too
  "bar": 2, // camma will be stripped,
  "baz": [1,2,3,]
}`;

console.log(fixJSON(json_demo));

// Outputs:
// {
//   "foo": 1,
//   "bar": 2,
//   "baz": [1,2,3]
// }