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Get greatest repetitive item in array JavaScript
We have an array of Number / String literals that contains some values (some are repetitive as well). Our job is to write a function that returns the element from the array which appears for the greatest number of times in the array.
For example − if the input array is −
const input = ['a', 'v', 'k', 'f', 'a', 'f', 's', 'd', 'd', 'f', 'a', 'j', 'a'];
Then the output should be −
'a'
because 'a' gets repeated for the maximum number of times
Therefore, let’s write the code for this. We will use a Map() to keep track of all the elements we encounter and their count, and at last return the element with maximum count like this −
Example
const input = ['m', 'a', 'v', 'k', 'f', 'a', 'f', 's', 'd', 'd', 'f', 'a',
'j', 'a'];
const findMaximum = arr => {
const map = arr.reduce((acc, val) => {
let count = acc.get(val);
if(count){
acc.set(val, ++count);
} else {
acc.set(val, 1);
};
return acc;
}, new Map());
return Array.from(map).reduce((acc, val) => {
if(val[1] > acc[1]){
return val;
};
return acc;
}, [0, 0])[0];
};
console.log(findMaximum(input));Output
The output in the console will be −
a
Updated on: 28-Aug-2020
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