[tk.stas]

<script>
var people = [
  { "name": "bob", "dinner": "pizza" },
  { "name": "john", "dinner": "sushi" },
  { "name": "john", "dinner": "hummus" }
];
var str = "sushi";

var obj = people.filter(function (person) { return Object.values(person).some(function(val) {
  return val.toUpperCase() == str.toUpperCase()
})});
document.write(JSON.stringify(obj, null, 4))

</script>

Uncaught TypeError: val.toUpperCase is not a function - если в объекте есть еще массив.

var people = [
  { "name": "bob", "dinner": [ "sushi", "pizza" ] },
  { "name": "john", "dinner": "sushi" },
  { "name": "john", "dinner": "hummus" }
];