findTypes.js

// Find all nested instances of _type `type`
const findAssets = (object, type, results = []) => {
  if (object instanceof Object) {
    if (object["_type"] === type) {
      results.push(object);
      return;
    }

    for (const key of Object.keys(object)) {
      const value = object[key];
      if (Array.isArray(value)) {
        value.forEach((v) => findAssets(v, type, results));
      } else if (value instanceof Object) {
        findAssets(object[key], type, results);
      }
    }
  }

  return results;
};