function mergeArray(arr) {
  var mergedArray = [];
  
  for (var i = 0; i < arr.length; i++) {
    var currentElement = arr[i];
    
    if (mergedArray.indexOf(currentElement) === -1) {
      mergedArray.push(currentElement);
    }
  }
  
  return mergedArray;
}

var array = [1, 2, 3, 2, 4, 5, 4, 6];
var mergedArray = mergeArray(array);
console.log(mergedArray); // 输出 [1, 2, 3, 4, 5, 6]