Check if an array contains duplicate values

Question

I wanted to write a javascript function which checks if array contains duplicate values or not.

I have written the following code but its giving answer as "true" always.

Can anybody please tell me what am I missing.

function checkIfArrayIsUnique(myArray)      {         for (var i = 0; i < myArray.length; i++)          {             for (var j = 0; j < myArray.length; j++)              {                 if (i != j)                  {                     if (myArray[i] == myArray[j])                      {                         return true; // means there are duplicate values                     }                 }             }         }         return false; // means there are no duplicate values.     } 

Answer 1

An easy solution, if you've got ES6, uses Set:

function checkIfArrayIsUnique(myArray) {    return myArray.length === new Set(myArray).size;  }    let uniqueArray = [1, 2, 3, 4, 5];  console.log(`${uniqueArray} is unique : ${checkIfArrayIsUnique(uniqueArray)}`);    let nonUniqueArray = [1, 1, 2, 3, 4, 5];  console.log(`${nonUniqueArray} is unique : ${checkIfArrayIsUnique(nonUniqueArray)}`);