getValueFromPath.js

function getValueFromPath(object, path) {
  const OBJECT_TYPE = '[object Object]';
  const $type = Function.prototype.call.bind(Object.prototype.toString);
  
  // Ensure that path is a string, default to an empty string if not provided.
  // Replace bracket notation occurrences on path with dot notation.
  // Split path (to array) using the `.` delimeter, discard empty elements.
  path = (path ? String(path) : String())
    .replace(/\[((?:['"])?)([^[\]]*)\1\]/g, function __replacer__($, $$, key) {
      return `.${Number(key) || String(key)}`;
    })
    .split(/\.+/)
    .filter(Boolean);

  // Value is originally the root object.
  let value = object;

  // For every key in the path array, try to access the value at that address.
  // Update `value` with the value at that address.
  // Break the loop if `value` is `undefined`.
  for (const key of path) {
    // If value is an object instance or plain JS object and has the given key,
    // access the given key on the object. Otherwise, if it is an array, try to
    // access the numeric key(index) on the array. Otherwise, it is `undefined`.
    try {
      value = (value instanceof Object || $type(value) === OBJECT_TYPE) && key in value
        ? value[key]
        : value[value instanceof Array ? Number(key) : key];

      if (value === undefined) break;
    } catch (e) {
      value = undefined;
      break;
    }
  }

  return value;
}