title: How to merge objects by key in javascript with Lodash
body: <p>I have this array of objects:</p>
  
  <pre><code>[
    {
      id: 1, oid: 5, 
      dates: { 
        5: {start_date: "12.30", end_date: "12.31" },
        14: {start_date: "01.01", end_date: "01.15" }
      }
    },
    {
      id: 2, oid: 5, 
      dates: { 
        17: {start_date: "02.01", end_date: "02.20" },
        19: {start_date: "03.01", end_date: "03.10" }
      }
    }
  ]
  </code></pre>
  
  <p>How to merge by "dates" key and get this result with Lodash</p>
  
  <pre><code>{
    5: {start_date: "12.30", end_date: "12.31" },
    14: {start_date: "01.01", end_date: "01.15" },
    17: {start_date: "02.01", end_date: "02.20" },
    19: {start_date: "03.01", end_date: "03.10" }
  }
  </code></pre>