mapValues.md

title	tags
mapValues	object,function,intermediate

Creates an object with the same keys as the provided object and values generated by running the provided function for each value.

• Use Object.keys(obj) to iterate over the object's keys.
• Use Array.prototype.reduce() to create a new object with the same keys and mapped values using fn.

const mapValues = (obj, fn) =>
  Object.keys(obj).reduce((acc, k) => {
    acc[k] = fn(obj[k], k, obj);
    return acc;
  }, {});

const users = {
  fred: { user: 'fred', age: 40 },
  pebbles: { user: 'pebbles', age: 1 }
};
mapValues(users, u => u.age); // { fred: 40, pebbles: 1 }