title: Proper way to add property to every object inside an object
body: <p>I'm iterating an object that has many objects of the same type inside it. On each object I need to add a property running through the entire object. I manage to do this with <code>reduce</code> but this is pretty ugly to read and I believe must have something more readable to do.</p>
  <p>I need to keep the object keys, but just add a prop on each.</p>
  <pre class="lang-js prettyprint-override"><code>const myObj = {
    key1: { /* data */ },
    key2: { /* data */ },
    key3: { /* data */ }
  }
  
  Object.keys(myObj).reduce((acc, value) =&gt; ({
    ...acc,
    [value]: {
      ...myObj[value],
      newProperty: 'foo',
    },
  }), {});
  </code></pre>
  <p>I believed that lodash must have something that make this better, but I fail to find something that does the trick even on lodash or using the array/object API.</p>