Checks if a given array has multiple items of the same data type next to each other. In the test code it checks if a given array has three numbers cohesively. Using reducer and only one line

checkIfArrayHasNValuesOfSameDataTypeCohesively_oneLiner.js

const array1 = [1,2,'a',3,'b',4,5]
const array2 = [1,2,'a',3,'b',4,5,6,'k']

const checkIfArrayHasNValuesOfSameDataTypeCohesively = datatype => n => array => (array.reduce((acc, val) => (
    {passed: acc.passed || (acc.n = typeof val != datatype ? 0 : acc.n + 1) >= n, n: acc.n}
), {n: 0, passed: false})).passed;

const hasThreeNumbersCohesively = checkIfArrayHasNValuesOfSameDataTypeCohesively('number')(3);
console.log(hasThreeNumbersCohesively(array1)); // false
console.log(hasThreeNumbersCohesively(array2)); // true