Solucao

extract_property_recursively.js

const formatters = {
  current: {
      count: {
        value: 'numeric',
          percent: 'percent'
      },
    sum: {
      value: 'currency'
    }
  }
}

const getFormatter = (key, obj=null) => {
  let match = key.match(/([aA-zZ]+)\.?(([aA-zZ]{1,40}\.?)*)/);
  if(typeof obj == "object") {
  	return getFormatter(match[2], obj[match[1]]);
  } else {
  	return obj;
  }
}

const test1 = getFormatter('current.count.value', formatters) // numeric
const test2 = getFormatter('current.count.percent', formatters) // percent
const test3 = getFormatter('current.sum.value', formatters) // currency


console.log(test1, test2, test3);