Find unique and biggest string values from an array in JavaScript

Let’s say, we have an array of objects like this −

Example

const arr = [
   {text:'use'},
   {text: 'secur'},
   {text: 'form'},
   {text: 'user'},
   {text: 'users'},
   {text: 'form'},
   {text: 'secur'},
   {text: 'sec'},
   {text: 'users'},
   {text: 'secu'},
   {text: 'secur'},
   {text: 'for'},
   {text: 'form'}
]

Our job is to write a function that takes in this array and a number n and the function should return an array of n objects which have the longest string value for the text key and all the objects should have a unique value for the text key. If there doesn’t exist n unique objects, then we should return all unique objects.

Therefore, let’s write the code for this function −

Example

const arr = [
   {text: 'use'},
   {text: 'secur'},
   {text: 'form'},
   {text: 'user'},
   {text: 'users'},
   {text: 'form'},
   {text: 'secur'},
   {text: 'sec'},
   {text: 'users'},
   {text: 'secu'},
   {text: 'secur'},
   {text: 'for'},
   {text: 'form'}
];
const sorter = (a, b) => {
   return b.text.length - a.text.length;
}
const longestUnique = (arr, num) => {
   const copy = arr.slice();
   copy.sort(sorter);
   const map = new Map();
   const uniqueCopy = copy.filter(el => {
      const exists = map.get(el.text);
      if(exists){
         return false;
      };
      map.set(el.text, 1);
      return true;
   });
   return uniqueCopy.splice(0, num);
}
console.log(longestUnique(arr, 4));
console.log(longestUnique(arr, 12));

Output

The output in the console will be −

[
   { text: 'secur' },
   { text: 'users' },
   { text: 'form' },
   { text: 'user' }
]
[
   { text: 'secur' },
   { text: 'users' },
   { text: 'form' },
   { text: 'user' },
   { text: 'secu' },
   { text: 'use' },
   { text: 'sec' },
   { text: 'for' }
]