Javascript 向水线模型添加自定义属性

由于嵌套填充不可用，我需要手动传递自定义属性。在我的具体案例中，这意味着：一个客户有许多项目，一个项目有许多贡献者

Customer.find().populate('projects').exec(function(err, customer) {

反应看起来像

[
    {
        "projects": [
            { "name": "First project" }
        ],
        "customer": "John Doe"
    },
    {
        "projects": [
            { "name": "Another project" },
            { "name": "And another one" }
        ],
        "customer": "Susan Doe"
    }
]

我正在迭代这些项目，希望附加一个

contributors

属性。我试过了

customer.forEach(function(customer, index) {
    customer.projects.forEach(function(project, index) {
        ProjectContributor.find({
            project: project.id
        }).exec(function(err, contributor) {
            project.contributors = contributors;
        });

---

但是

project.contributors

仍然没有定义。为什么？如何附加这些自定义属性？

代码中有许多错误

Customer.find().populate('projects').exec(function(err, customers) {
  customers.forEach(function(customer, index) {
    customer.projects.forEach(function(project, index) {
      ProjectContributor.findOne({project: project.id}) // use findOne since you only want one project at a time
      .populate('contributors')
      .exec(function(err, projectContributor) {
        project.contributors = projectContributor.contributors; // contributors is in projectContributor
      });
    });
  });
});