JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.11.1/lodash.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash-fp/0.10.4/lodash-fp.js"></script>

JavaScript

var objs = {
  obj1 : [{ amount: 5, new: true }, { amount: 3, new: false }],
  obj2: [{ amount: 1, new: true }, { amount: 2, new: false }]
};

var result = _.compose(_.maxBy('amount'), _.filter('new'), _.flatten, _.values)(objs);

alert(JSON.stringify(result));