const splitStrings = (a, sep = '/') => a.map(i => i.split(sep));


const elAt = i => a => a[i];


const rotate = a => a[0].map((e, i) => a.map(elAt(i)));


const allElementsEqual = arr => arr.every(e => e === arr[0]);


const commonPath = (input, sep = '/') => rotate(splitStrings(input, sep))
    .filter(allElementsEqual).map(elAt(0)).join(sep);

const cdpInput = [
  '/home/user1/tmp/coverage/test',
  '/home/user1/tmp/covert/operator',
  '/home/user1/tmp/coven/members',
];

console.log(`Common path is: ${commonPath(cdpInput)}`);