Bad request(400) for POST request on django rest-framework api via jquery

Question

I am quite new to django and jquery. I am trying to perform a post request on:

my model

class part_list(models.Model):

    designID = models.ForeignKey('modules', on_delete=models.CASCADE)
    PartID = models.ForeignKey('parts',on_delete=models.CASCADE)
    quantity = models.IntegerField()

    def __str__(self):
        return "DesignID :{}, PartID :{}".format(self.designID,self.PartID)


    class Meta:
        unique_together = (('designID','PartID'))

my serializer

class sub_part_list_serializer(serializers.ModelSerializer):

    class Meta:
        model = part_list
        fields = ('designID', 'PartID', 'quantity')

my view

class sub_part(generics.ListCreateAPIView):
    serializer_class = sub_part_list_serializer

    def get_queryset(self):
        queryset = part_list.objects.all()
        designID = self.request.query_params.get('designID',None)
        print(self.request)
        if designID is not None:
            queryset = queryset.filter(designID__exact=designID)
        return queryset

and my jquery

$('#test').on('click', function(){

        var data1 = {};
        data1["designID"] = "bar-123";
        data1["PartID"] = "A102";
        data1["quantity"] = 3;
        console.log(data1);

        $.ajax({
            type: "POST",
            url: "bon/sub_part/",
            data: data1,
            contentType: "application/json; charset=utf-8",
            success: function(data){
                alert(data);
            },
            error: function(XMLHttpRequest, textStatus, errorThrown) {
                alert("some error " + String(errorThrown) + String(textStatus) + String(XMLHttpRequest.responseText));
            }
        });

the error it is showing is

Bad Requesterror{"detail":"JSON parse error - Expecting value: line 1 column 1 (char 0)"}

when I am making post requests directly from the API it is working fine. I am not using any user authentication. I also tried to add the csrf token in the request header but nothing changed

Please Help!