lambda functions in javascript

lambda.js

var lambda = function (str) {
  var res = str.match(/^\s*([a-z]+(?:\s+[a-z]+)*)\s*\->\s*(.+?)\s*$/);
  
  if (!res) {
    throw new Error('Invalid lambda expression');
  }
  
  var args = res[1].replace(/\s{2,}/g, ' ').split(' ')
    , body = 'return ' + res[2] + ';';
  
  return new Function(args, body);
};

var data = [
  {name: 'Bill', age: 30},
  {name: 'Susan', age: 29}
];

var names = data.map(lambda("x -> x.name")); // ['Bill', 'Susan']

var totalAge = data.reduce(lambda("m x -> m + x.age"), 0); // 59