js数组中两个有相同删除一个

for (var i = 0; i < project.Before.length; i++) {
                    var j = 0;
                    for (j = 0; j < data.length; j++) {
                        if (project.Before[i].ProjectBeforeObject != null && project.Before[i].ProjectBeforeObject.CZ == data[j].DEPTNAME) {
                            project.Before[i].ProjectBeforeObject.SEQ = data[j].SEQ;
                            break;
                        }
                    }
                    if (j == data.length) {
                        project.Before.splice(i, 1);
                        i--;
                    }
                }