How to filter out common array in array of arrays in JavaScript

JavascriptWeb DevelopmentFront End TechnologyObject Oriented Programming

Suppose we have an array of arrays like this −

const arr = [
   [
      "Serta",
      "Black Friday"
   ],
   [
      "Serta",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ]
];

We are required to write a JavaScript function that takes in one such array. And the function should return a new array that contains all the unique subarrays from the original array.

The code for this will be −

const arr = [
   [
      "Serta",
      "Black Friday"
   ],
   [
      "Serta",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ],
   [
      "Simmons",
      "Black Friday"
   ]
];
const filterCommon = arr => {
   const map = Object.create(null);
   let res = [];
   res = arr.filter(el => {
      const str = JSON.stringify(el);
      const bool = !map[str];
      map[str] = true;
      return bool;
   });
   return res;
};
console.log(filterCommon(arr));

Output

The output in the console −

[ [ 'Serta', 'Black Friday' ], [ 'Simmons', 'Black Friday' ] ]
raja
Published on 12-Oct-2020 11:24:19
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