Immutably rename object keys

JavaScript version

const renameKeys = (keysMap, obj) => Object.keys(obj).reduce((acc, key) => ({ ...acc, ...{ [keysMap[key] || key]: obj[key] } }), {});

Examples

const obj = { a: 1, b: 2, c: 3 };
const keysMap = { a: 'd', b: 'e', c: 'f' };
renameKeys(keysMap, obj); // { d: 1, e: 2, f: 3 }