Using lodash _.extend to extend my object in server side function

My jsbin link is here: http://jsbin.com/siyux/1/edit

Below is my code:

var dest = {
owner: '53a96efe07b7570013bdcb8b',
schedule: 'Thu Jul 03 2014 20:00:00 GMT+0530 (India Standard Time)',
_id: '53b55f52dafac9f40984fe30',
__v: 0,
a: [],
result:{
markCard: []
},
parent: {},
b: [],
c: [],
d: { teamRef: '53ad727d62290bc8178695fa', squad: [] },
e: { teamRef: '53ad726e62290bc8178695f9', squad: [] }
};

var src = {
markCard:
[ { i: 1,
bt: [Object],
bl: [Object],
ts: [Object],
sc: [Object] },
{ i: 2,
bt: [Object],
bl: [Object],
ts: [Object],
sc: [Object] } ],
srcA:
{ __v: 0,
_id: '53ad726e62290bc8178695f9',
name: 'T-H',
owner: '53a96efe07b7570013bdcb8b' },
srcB: { __v: 0,
_id: '53ad726e62290bc8178695f0',
name: 'T-M',
owner: '53a96efe07b7570013bdcb8b' },
srcC: false,
srcD: 'Bt'
};

//console.log(_.merge(dest, src));
dest.result=_.extend(dest.result, src);
console.log(dest);

*Expected Output:*

dest = {
owner: '53a96efe07b7570013bdcb8b',
schedule: 'Thu Jul 03 2014 20:00:00 GMT+0530 (India Standard Time)',
_id: '53b55f52dafac9f40984fe30',
__v: 0,
a: [],
result:{
markCard:
[ { i: 1,
bt: [Object],
bl: [Object],
ts: [Object],
sc: [Object] },
{ i: 2,
bt: [Object],
bl: [Object],
ts: [Object],
sc: [Object] } ],
srcA:
{ __v: 0,
_id: '53ad726e62290bc8178695f9',
name: 'T-H',
owner: '53a96efe07b7570013bdcb8b' },
srcB: { __v: 0,
_id: '53ad726e62290bc8178695f0',
name: 'T-M',
owner: '53a96efe07b7570013bdcb8b' },
srcC: false,
srcD: 'Bt'
},
parent: {},
b: [],
c: [],
d: { teamRef: '53ad727d62290bc8178695fa', squad: [] },
e: { teamRef: '53ad726e62290bc8178695f9', squad: [] }
};

*Actual Output*

dest = {
owner: '53a96efe07b7570013bdcb8b',
schedule: 'Thu Jul 03 2014 20:00:00 GMT+0530 (India Standard Time)',
_id: '53b55f52dafac9f40984fe30',
__v: 0,
a: [],
result:{
markCard:
[ { i: 1,
bt: [Object],
bl: [Object],
ts: [Object],
sc: [Object] },
{ i: 2,
bt: [Object],
bl: [Object],
ts: [Object],
sc: [Object] } ],
srcA:
{ },
srcB: { }
},
parent: {},
b: [],
c: [],
d: { teamRef: '53ad727d62290bc8178695fa', squad: [] },
e: { teamRef: '53ad726e62290bc8178695f9', squad: [] }
};

As a result of extending, I am not able to extend the values of srcA, and
srcB to the destination. Only the structure gets copied i guess. Some one
please let me know where I am wrong. Thanks.