Merging two JSON data in nodejs

I want to add the two JSON data in to one object..

this is Array name as MAPPER.

[ MAPPER {
     FieldOne: 'JCI',
     FieldTwo: 'PUNE',
     FieldThree: 'Shashank.dahake
     FieldFour: '8600429335' } ]

And our json file is

[
{
userId: "1",
Title: "js",
Status: "done"
},
{
userId: "2",
Title: "nodejs",
Status: "pending"
},
{
userId: "3",
Title: "node1",
Status: "done"
}
]

what i want is to add this two into one JSON data..

so our final file will look like

[
    {
        userId: "1",
        Title: "js",
        Status: "done",
        FieldOne: 'JCI',
        FieldTwo: 'PUNE',
        FieldThree: 'Shashank.dahake
        FieldFour: '8600429335' 
    }
    and so on...
]

if any one this please share up the things.. Thanks in advance..

via SasaD