buildAdvancedFieldLocationTreeArray.js

/**
 * Builds an array of object structure from an object with parallel values.
 * Expects the same number of entries in each array.
 * Similar to building a pivot table, but with a tree structure.
 * 
 * @param data Object with parallel values in arrays.
 * @param separator String to use as a separator in the keys from the data.
 * @returns Array of objects with the keys from the data and the values from the data arranged hierarchically.
 * @example
 * // The data is in the form:
 * {
 *   "country": ["USA", "USA", "USA", null, "USA", null, "France"],
 *     "state": ["CA", "CA", "NY", null, "TX", "Michigan", null],
 *       "city": ["Los Angeles", "San Francisco", "New York", "Abidjan", null, null, "Paris"]
 * }
 *
 * // The output should be:
 * [{
 *   "label": "USA", "id": "USA", "children": [
 *     {
 *       "label": "CA", "id": "USA|CA", "children": [
 *         { "label": "Los Angeles", "id": "USA|CA|Los Angeles" },
 *         { "label": "San Francisco", "id": "USA|CA|San Francisco" }]
 *     },
 *     {
 *       "label": "NY", "id": "USA|NY", "children": [
 *         { "label": "New York", "id": "USA|NY|New York" }]
 *     },
 *     { "label": "TX", "id": "USA|TX" }
 *   ]
 * },
 * { "label": "Abidjan", "id": "||Abidjan" },
 * { "label": "Michigan", "id": "|Michigan" },
 * {
 *   "label": "France", "id": "France", "children": [
 *     { "label": "Paris", "id": "France||Paris" }]
 * }]
 */
function buildAdvancedFieldLocationTreeArray(data, separator = "|") {
  let dataTree = {};
  let dataArray = [];
  for (let i = 0; i < data.country.length; i++) {
    const [country, state, city] = [data.country[i], (data.state ? data.state[i] : null), (data.city ? data.city[i] : null)];
    // fill up the tree from country, state, and city
    if (country && !(country in dataTree)) {
      dataTree[country] = {
        label: country,
        id: country
      };
    }
    if (country && state) {
      dataTree[country].children = dataTree[country].children || {};
      const stateKey = `${country}${separator}${state}`;
      if (!(stateKey in dataTree[country].children)) {
        dataTree[country].children[stateKey] = {
          label: state,
          id: stateKey
        };
      }
    }
    if (country && state && city) {
      const stateKey = `${country}${separator}${state}`;
      const cityKey = `${country}${separator}${state}${separator}${city}`;
      dataTree[country].children[stateKey].children = dataTree[country].children[stateKey].children || {};
      if (!(cityKey in dataTree[country].children[stateKey].children)) {
        dataTree[country].children[stateKey].children[cityKey] = {
          label: city,
          id: cityKey
        };
      }
    }
    // fill up the tree for state and city
    if (!country && state && city) {
      const stateKey = `${separator}${state}`;
      if (!(stateKey in dataTree)) {
        dataTree[stateKey] = {
          label: state,
          id: stateKey
        };
      }
      const cityKey = `${separator}${state}${separator}${city}`;
      if (!(cityKey in dataTree[stateKey].children)) {
        dataTree[stateKey].children[cityKey] = {
          label: city,
          id: cityKey
        };
      }
    }
    // fill up the tree for country and city
    if (country && !state && city) {
      const cityKey = `${country}${separator}${separator}${city}`;
      dataTree[country].children = dataTree[country].children || {};
      if (!(cityKey in dataTree[country].children)) {
        dataTree[country].children[cityKey] = {
          label: city,
          id: cityKey
        };
      }
    }
    // fill up the tree for city only
    if (!country && !state && city) {
      const cityKey = `${separator}${separator}${city}`;
      if (!(cityKey in dataTree)) {
        dataTree[cityKey] = {
          label: city,
          id: cityKey
        };
      }
    }
    // fill up the tree for state only
    if (!country && state && !city) {
      const stateKey = `${separator}${state}`;
      if (!(stateKey in dataTree)) {
        dataTree[stateKey] = {
          label: state,
          id: stateKey
        };
      }
    }
  }

  // flatten the tree structure for the custom widget
  dataArray = flattenTree(dataTree);

  return dataArray;
}

flattenTree function in https://gist.github.com/julio73/c24b48f690008ac4862edfffb337d35c