如何在Mongodb中转换ObjectId？我尝试过不同的方法，但仍然会出错

Question

//模式设置

var campgroundSchema = new mongoose.Schema({
    name: String,
    image: String,
    description: String
})

var campground = mongoose.model("campground", campgroundSchema)


#The error is where coming from here, don't seem to get the campgrounds diplayed
app.get("/campgrounds/:id", function(req, res){
    //find the campground with provided ID
    campground.findById(req.params.id, function(err, foundCampground){
        if(err){
            console.log(err)
        } else {
            //render show template
            res.render("show", {campground: foundCampground})
        }
    })
})
    

**消息：“转换为ObjectId失败，因为模型“CampGrand”的路径“_id”处的值“5e61150b58e80830240ef790”，名称：“CastError”，模型：模型{CampGrand}**

Answer 1

您可以使用mongoose将字符串转换为MongoId。类型。ObjectId（）方法，并将字符串作为第一个参数传递。

例如，使用上述方法后，您的代码如下所示

app.get("/campgrounds/:id", function(req, res){
    //find the campground with provided ID
    campground.findById(
      mongoose.Types.ObjectId(req.params.id),
      function(err, foundCampground){
        if(err){
            console.log(err)
        } else {
            //render show template
            res.render("show", {campground: foundCampground})
        }
    })
});

Answer 2

当您创建这样的模式时，您可以传递{_id： false}

var campgroundSchema = new mongoose.Schema({
    name: String,
    image: String,
    description: String
}, { _id: false })