Underscore.js object-object mapper?

Question

Is there an Underscore.js function that can map one object to another object, based on the other object's properties?

(Kind of how AutoMapper works in .NET.)

For example:

var objectA = { 'name': 'Jonathan', 'city': 'Sydney' };
var objectB = { 'name': 'Jonathan Conway', 'city': 'Sydney', 'errors': [] }

_.mapperMethod(objectB);

=> { 'name': 'Jonathan Conway', 'city': 'Sydney' };

Answer 1

Possibly _.extend():

_.extend(objectA, objectB);

console.log(objectA);
// { 'name': 'Jonathan Conway', 'city': 'Sydney', 'errors': [] }

If you don't want to pick up additional keys, you can use it with _.keys() and _.pick():

var keys = _.keys(objectA);
_.extend(objectA, _.pick(objectB, keys));

console.log(objectA);
// { 'name': 'Jonathan Conway', 'city': 'Sydney' }