Upper or lower elements count in an array in JavaScript


Consider we have an array of Numbers that looks like this −

const array = [54,54,65,73,43,78,54,54,76,3,23,78];

We are required to write a function that counts how many of the elements are in the array below / above a given number.

For example, if the number is 60 −

The answer should be 5 elements below it (54,54,43,3,23) and 5 element par it (65,73,78,76,78) Therefore, let’s write the code for this function −

Example

The code for this will be −

const array = [54,54,65,73,43,78,54,54,76,3,23,78];
const belowParNumbers = (arr, num) => {
   return arr.reduce((acc, val) => {
      const legend = ['par', 'below'];
      const isBelow = val < num;
      acc[legend[+isBelow]]++;
      return acc;
   }, {
      below: 0,
      par: 0
   });
};
console.log(belowParNumbers(array, 50));
console.log(belowParNumbers(array, 60));
console.log(belowParNumbers(array, 70));

Output

The output in the console will be −

{ below: 3, par: 9 }
{ below: 7, par: 5 }
{ below: 8, par: 4 }

Updated on: 20-Oct-2020

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