title: How to filter out duplicates from a nested object array?
body: <p>I currently have a nested geojson array with duplicate values. How can I filter out these values based on the OBJECT ID?</p>
  
  <pre><code>let geojson = [
    {properties: {OBJECTID: 6249646, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}}, 
    {properties: {OBJECTID: 6249646, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}}, 
    {properties: {OBJECTID: 6249647, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}},
    {properties: {OBJECTID: 6249647, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}},
    {properties: {OBJECTID: 6249648, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}},
    {properties: {OBJECTID: 6249649, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}} 
    ]
  </code></pre>
  
  <p>What I would like to return is a json array with unique values, like this:</p>
  
  <pre><code>[ 
    {properties: {OBJECTID: 6249646, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}}, 
    {properties: {OBJECTID: 6249647, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}},
    {properties: {OBJECTID: 6249648, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}},
    {properties: {OBJECTID: 6249649, FeatureCode: 10185, Version: 3, VersionDate: "1/25/2018"}} 
  ]
  
  </code></pre>