nodejs post method is not saving data
<p>i have post method which is working fine when i do as shown below</p>

<pre><code>var companyDetailsModel = mongoose.model('companyDetails')
router.post('/companyDetails', function(req, res, next) {
    var newCompanyDetails = new companyDetailsModel();

    newCompanyDetails.companyName=req.body.companyName;
    newCompanyDetails.streetAddress=req.body.streetAddress;
    newCompanyDetails.city=req.body.city;
    newCompanyDetails.Street=req.body.Street;
    newCompanyDetails.ZipCode=req.body.ZipCode;
    newCompanyDetails.Phone=req.body.Phone;
    newCompanyDetails.Fax=req.body.Fax;
    newCompanyDetails.webSite=req.body.webSite;
    newCompanyDetails.Logo=req.body.Logo;

    newCompanyDetails.save(function(err) {
        if (err){
            console.log('Error in Saving user: '+err);
        }
        console.log('User Registration succesful');
        res.send("user added sucessfully");
    });

})
</code></pre>

<p>this route works fine and data is saved in the database but if i try to do it as shown below</p>

<pre><code>router.post('/companyDetails', function(req, res, next) {
    var newCompanyDetails = new companyDetailsModel();
    newCompanyDetails= req.body;
    newCompanyDetails.save(function(err) {
        if (err){
            console.log('Error in Saving user: '+err);
        }
        console.log('User Registration succesful');
        res.send("user added sucessfully");
    });

})
</code></pre>

<p>i will get internal server error like newCompanyDetails.save is not a function please say why is this behavior if a post request contains 100 of  fields should i explicitly should i  assign all the fields please help me understand this</p>