CSV to something

transform.js

var data = [
  ['Prefecture', 'A', 'B', 'C'],
  ['Tokyo', '1', '2', '3'],
  ['Kanagawa', '4', '5', '6']
];

var labels = data[0];
var dataSet = data.slice(1).reduce(function(acc, row) {
  var item = {};
  item[labels[0]] = row[0];
  item.values = row.slice(1).map(function(value, i) {
    return { key: labels[i + 1], value: parseInt(value, 10) };
  });
  acc.push(item);
  return acc;
}, []);

console.log(dataSet);