flatten a nested JavaScript object to a flatten one-level object

object-flatten.js

// Adapted from source: https://stackoverflow.com/a/19204980
const flatten = (function(isArray, wrapped) {
  return function(table) {
    return reduce('', {}, table);
  };

  function reduce(path, accumulator, table) {
    if (isArray(table)) {
      const length = table.length;

      if (length) {
        let index = 0;

        while (index < length) {
          const property = path + '[' + index + ']';
          const item = table[index++];

          if (wrapped(item) === item) {
            reduce(property, accumulator, item);
          } else {
            accumulator[property] = item;
          }
        }
      } else accumulator[path] = table;
    } else {
      let empty = true;
      let item;
      let property;

      if (path) {
        for (property in table) {
          item = table[property];
          property = path + '.' + property;
          empty = false;

          if (wrapped(item) === item) {
            reduce(property, accumulator, item);
          } else {
            accumulator[property] = item;
          }
        }
      } else {
        for (property in table) {
          item = table[property];
          empty = false;

          if (wrapped(item) === item) {
            reduce(property, accumulator, item);
          } else {
            accumulator[property] = item;
          }
        }
      }

      if (empty) {
        accumulator[path] = table;
      }
    }

    return accumulator;
  }
})(Array.isArray, Object);