JSFiddle - React, Tailwind, and code Playground

JavaScript

var pLines={};

function countPLines(data){
	var pl = data.split(',');
	pl.forEach(function(entry){
		
		pLines[entry] = (pLines[entry] || 0) + 1;

	});
}

var data =["a_b", "a b,b", "c", "c", "a,a b"];

data.forEach(function(ele){
  countPLines(ele);
})

console.log(pLines);
console.log(Object.keys(pLines));
console.log(Object.values(pLines));