Converting circular structure to JSON in JS

README.md

When does this error occur?

This error occurs when you try to convert a JavaScript object to JSON, but the object contains a circular reference. A circular reference occurs when an object refers to itself, directly or indirectly.

stringify.js

function stringify(obj) {
  let cache = [];
  let str = JSON.stringify(obj, function(key, value) {
    if (typeof value === "object" && value !== null) {
      if (cache.indexOf(value) !== -1) {
        // Circular reference found, discard key
        return;
      }
      // Store value in our collection
      cache.push(value);
    }
    return value;
  });
  cache = null; // reset the cache
  return str;
}