How to get unique values of an array using JavaScript

Question: How to get unique values of an array using JavaScript?

Answer:

Given array.

var givenArray = [10, 10, 10, 20, 20, 30, 30, 30, 30, 30, 40, 50, 50, 60];

JavaScript function using new prototype "contains" and "unique".

Array.prototype.contains = function(v) {
  for (var i = 0; i < this.length; i++) {
    if (this[i] === v) return true;
  }
  return false;
};

Array.prototype.unique = function() {
  var arr = [];
  for (var i = 0; i < this.length; i++) {
    if (!arr.contains(this[i])) {
      arr.push(this[i]);
    }
  }
  return arr;
}

var duplicates = [1, 3, 4, 2, 1, 2, 3, 8];
var uniques = duplicates.unique(); 

console.log(uniques);

JavaScript function using for loop.

function uniqueValue(array){
  var outputArray = [];
  var count = 0;
  var start = false;
          
  for (j = 0; j < array.length; j++) {
    for (k = 0; k < outputArray.length; k++) {
      if ( array[j] == outputArray[k] ) {
        start = true;
      }
     }
     count++;
     if (count == 1 && start == false) {
       outputArray.push(array[j]);
     }
     start = false;
     count = 0;
   }
 return outputArray;
}


console.log(uniqueValue(myArray));

output:

[10, 20, 30, 40, 50, 60]

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