JSFiddle - React, Tailwind, and code Playground

HTML

<div id="output"></div>

JavaScript

var origArray = [{
    "Name": "Single",
    "URL": "xxx",
    "ID": 123
    },
{
    "Name": "Double",
    "URL": "yyy",
    "ID":  345
    },
{
    "Name": "Family",
    "URL": "zzz",
    "ID": 567
    }];

var destArray = [{
    "Name": "Single",
    "URL": "xxx",
    "ID": 123
    },
{
    "Name": "Double",
    "URL": "yyy",
    "ID":  888
    },
{
    "Name": "Family",
    "URL": "zzz",
    "ID": 567
    }];

var merged = origArray.concat(destArray);
var unique = merged.filter(function(item) {
    return ~this.indexOf(item.ID) ? false : this.push(item.ID);
}, []);

document.querySelector('#output').innerHTML = unique.reduce(function(p, item) {
    return p + 'ID: ' + item.ID + ', ';
}, '');