Destructures values from a `root` object based on one or more `nestedMaps` structures.

destruct.js

/**
 * Destructures values from a `root` object based on one or more `nestedMaps`
 * structures.
 * @param {Object} root
 *   The root object or array containing the data to destructure.
 * @param {...NestedMap} nestedMaps
 *   One or more nested mapping objects. Each key in the `NestedMap` is a
 *   string, and each value is either:
 *   - A string (which specifies the key in the result object), or
 *   - A `NestedMap` (which specifies further nested extraction).
 * @returns {Record<string, any>}
 *   An object containing the extracted values, with keys as specified by the
 *   `nestedMaps`.
 * @throws {Error}
 *   Throws an error if a recursive structure is detected in the `root` object.
 * @template {Record<string, string | NestedMap>} NestedMap
 */
function destruct(root, ...nestedMaps) {
  function recurse(root, nestedMap, seen) {
    for (const [key, value] of Object.entries(nestedMap)) {
      const rootValue = (+key < 0 && Array.isArray(root)) ? root.at(+key) : root[key];
      if (typeof value !== 'object') {
        returnValue[value] = rootValue;
      }
      else if (rootValue != null) {
        if (seen.includes(rootValue)) {
          throw new Error('Cannot use a recursive structure as the nested map.');
        }
        seen.push(rootValue);
        recurse(rootValue, value, seen);
      }
    }
  }

  // The object that will store the extracted values.
  const returnValue = {};

  // Iterate over each nested map and apply the recursion
  for (const nestedMap of nestedMaps) {
    recurse(root, nestedMap, []);
  }

  return returnValue;
}

~example.js

var data = {
  event: {
    app: "monday",
    type: "update_column_value",
    triggerTime: "2024-09-16T15:03:05.631Z",
    subscriptionId: 409408840,
    userId: -4,
    originalTriggerUuid: "1c097ddf26d7db04e785b6c3910812b6",
    boardId: 7438104037,
    groupId: "topics",
    pulseId: 7438104160,
    pulseName: "Item 1",
    columnId: "status",
    columnType: "color",
    columnTitle: "Status",
    value: {
      label: {
        index: 0,
        text: "Working on it",
        style: {
          color: "#fdab3d",
          border: "#e99729",
          var_name: "orange"
        },
        is_done: false
      },
      post_id: null
    },
    previousValue: {
      label: {
        index: 5,
        text: null,
        style: {
          color: "#c4c4c4",
          border: "#b0b0b0",
          var_name: "grey"
        },
        is_done: false
      },
      post_id: null
    },
    changedAt: 1726498985.1396656,
    isTopGroup: true,
    triggerUuid: "c48d7a18702d068c3a477cc8b7091b9c"
  },
  people: [
    'Chris',
    'Jamie',
    'Stacey'
  ]
};

console.log(
  extract(
    data,
    {
      people: {
        0: 'firstPerson',
        '-1': 'lastPerson'
      },
      event: {
        app: 'app',
        type: 'type',
        triggerTime: 'triggerTime',
      }
    },
    {people: 'people'}
  )
);