JavaScript: grab each nested object / flatten the top level of the object only

So I currently have part of an array of objects that looks like this:

props: {
       dog: {
         default: '',
         type: String
       },
       cat: {
         default: '',
         type: String
       },
       bird: {
         default: '',
         type: String
       }
      },
      {
       dog: {
         default: '',
         type: String
       },
       bird: {
         default: '',
         type: String
       },
       fish: {
         default: '',
         type: String
       }
     }

What I want is to essentially flatten the top level of the array of objects so that it has all the nested objects on the same level (and obviously without duplicates), like so:

{
   dog: {
     default: '',
     type: String
   },
   bird: {
     default: '',
     type: String
   },
   fish: {
     default: '',
     type: String
   }
}

This would be much easier if I knew what keys were always going to be in the structure, however I don't, so I need to be able to loop through it without specifying any key names. I've tried to at least grab each individual nested object and push each into an array like this:

const newArray = [];

for (let i = 0; i < objSize; i++) {
    // checks if properties exist
    if (JSON.stringify(petObj[i].options.props) !== '{}') {
      newArray.push(petObj[i].options.props);

      const numProps = Object.keys(newArray[i]).length;

      for (let j = 0; j < numProps.length; j++) {
        console.log(petObj[i].options.props[j]);
    }
  }

but that doesn't seem to be working since I get null/undefined errors after adding the inner for loop. Anyone care to offer a possible solution?