Build a one-level-depth object, by moving all nested objects to the first level

fromOneLevelDepth.js

// @private
var isObject = (value) =>
  value != null && typeof value === 'object';

/**
 * @private
 * Restores the one-level-depth object to the original nested object.
 *
 * @param  {Array} names: list of keys in the object
 * @param  {any} value: the value of the object to transform
 * @return {Object}
 */
function restoreDepth(names, value) {
  const key = names.shift();
  // determines whether is an index of array
  const obj = (key === '0' || +key) ? [] : {};
  if (names.length) {
    // recursively iterates over properties/items
    obj[key] = restoreDepth(names, value);
  } else {
    obj[key] = value;
  }
  return obj;
}

/**
 * @public
 * Converts a one-level-depth object (`{node-one: value}`)
 * to a nested object (`{node: {one: value}}`)
 *
 * @param  {Object} obj: Object to restore from `toOneLevelDepth`
 * @return {Object}
 */
function fromOneLevelDepth(obj) {
  let key, value, names;
  const newObj = {};
  if (!isObject(obj)) return obj;
  for (key in obj) {
    value = obj[key];
    names = key.split('-');
    jQuery.extend(true, newObj, restoreDepth(names, value));
    // merge(newObj, restoreDepth(names, value));
    // https://gist.github.com/jherax/05204bdf9eb47eeffdc8
  }
  return newObj;
}

toOneLevelDepth.js

// @private
var isObject = (value) =>
  value != null && typeof value === 'object';

/**
 * @public
 * Builds one-level-depth object by moving all nested objects to the first level.
 *
 * @param  {Object}  obj: Object to transform
 * @param  {Boolean} lowercase: (Optional) Determines whether the properties should be lowercase
 * @param  {String}  prefix: (Optional) Sets the initial prefix for the object to transform
 * @return {Object}  Object generated with one-level-depth
 */
function toOneLevelDepth(obj, lowercase, ...args) {
  const prefix = args[0];
  const newObj = {};
  let key, value, newKey;
  if (isObject(obj)) { // object and array
    for (key in obj) {
      value = obj[key];
      // prevents save empty values
      if (value === '' || value == null) continue;
      if (!prefix) newKey = key;
      else newKey = `${prefix}-${key}`;
      if (lowercase === true) newKey = newKey.toLowerCase();
      if (isObject(value)) { // objects and arrays
        // recursively iterates over properties/items
        jQuery.extend(true, newObj, toOneLevelDepth(value, lowercase, newKey));
        // merge(newObj, toOneLevelDepth(value, lowercase, newKey));
        // https://gist.github.com/jherax/05204bdf9eb47eeffdc8
      } else {
        newObj[newKey] = value;
      }
    } // end for
  } // end if
  return newObj;
}

usage.js

var user = {
    Coverage: 2,
    Applicant: {
      Holder: {
        Birth: "1990/01/01",
        FirstName: "Pepe",
        Gender: 1
      },
      Income: "00",
      Spouse: true
    }
};

// preserve camel-case
var obj1 = toOneLevelDepth(user);

// convert to lower-case
var obj2 = toOneLevelDepth(user, true);

// add the 'hc' prefix
var obj3 = toOneLevelDepth(user, true, 'hc');

console.log(user); // original object
console.log(obj1); // preserve camel-case
console.log(obj2); // convert to lower-case
console.log(obj3); // add the 'hc' prefix

// restores the object un-nested
var obj4 = fromOneLevelDepth(obj1);

console.log(obj4); // restored object
console.log(user); // original object

This utility can be used by Angular $location.search to pass a multi-level object as a parameter to the URL.