How can I determine if there is a duplicate dictionary in an array of dictionaries in JavaScript?

I have an array of dictionaries and I want to determine if there are any duplicate dictionaries. I tried using the _uniq method from Lodash.js and it looks like it’s finding unique dictionary objects but not determining if they’re equal. I also tried using the Set method which lets me store unique values of any type, whether primitive values or object references.

I know Lodash.js also has a method _.isEqual that determines equality between two unique dictionary objecs so it may be useful.

How can I determine if there is a duplicate dictionary in an array of dictionaries in JavaScript?

// The function should return True because there are two equal dictionaries
arr = [
    {
      "a": 1,
      "b": 2,
    },
    {
      "a": 1,
      "b": 2,
    }
];

// Lodash.js attempt
function hasDuplicate(arr) {
    return _uniq.(arr).length !== arr.length;
}

// Set attempt
function hasDuplicate(arr) {
    const noDuplicates = new Set(arr);
    return arr.length !== noDuplicates.size;
}