Unique Number of Occurrences Lab

30.6% Acceptance

This lab focuses on testing your ability to implement a function that checks the unique number of occurrences in an array of integers. The primary goal of the lab is to return true if the number of occurrences of each value in the given array is unique or false otherwise.

In this lab, you'll be provided with an initial setup that includes a function called uniqueOccurrences(arr) which takes an array of integers as input.


Your task is to implement and export the uniqueOccurrences function that fulfills the following requirements:

  • The input arr is an array of integers, with the length between 1 to 1000, and values ranging from -1000 to 1000.
  • The function should return a boolean value based on the uniqueness of occurrences of each integer in the array.


Example 1:

const arr1 = [1, 2, 2, 1, 1, 3]; const output1 = uniqueOccurrences(arr1); console.log(output1); // true

Explanation: The value 1 occurs 3 times, the value 2 occurs 2 times, and the value 3 occurs 1 time. No two values have the same number of occurrences.

Example 2:

const arr2 = [1, 2]; const output2 = uniqueOccurrences(arr2); console.log(output2); // false

Example 3:

const arr3 = [-3, 0, 1, -3, 1, 1, 1, -3, 10, 0]; const output3 = uniqueOccurrences(arr3); console.log(output3); // true


  1. Implement the uniqueOccurrences function and export it properly so that it can be imported in the evaluation script.
  2. Ensure that your implementation of uniqueOccurrences fulfills the requirements mentioned in the given examples and returns the expected output for those examples.

While implementing your solution, make sure that your code is bug-free, properly tested, and follows best practices.

Good luck!