airbnb/caravel

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
/**
 * Remove duplicate items from a list.
 */
export function removeDuplicates<T>(
  items: T[],
  hash?: (item: T) => unknown,
): T[] {
  if (hash) {
    const seen = new Set();
    return items.filter(x => {
      const itemHash = hash(x);
      if (seen.has(itemHash)) return false;
      seen.add(itemHash);
      return true;
    });
  }
  return [...new Set(items)];
}

export default removeDuplicates;