猫鼬：ValidationError：材料：在路径“材料”处因值“ ['glass']”而投射到数组失败

Question

下面是makerSchema

var makerSchema = new mongoose.Schema({
    materials:[{
        material:{
            type: String,
            required:[true, "Material is a required field"],
            trim:true,
            lowercase:true,
            enum:{
                values:['wood','metal','plastic','glass','concrete','other'], 
                message: 'Please choose from the given options only!'
            }
        }
    }]
},{
    timestamps:true
})

var Maker = mongoose.model('Maker', makerSchema);

我通过POST路由传递了以下数据，但收到错误

{
    "materials":["glass"]
}

我收到以下错误

ValidationError: materials: Cast to Array failed for value "[ 'glass' ]" at path "materials"

如何解决此错误并通过数组？

Answer 1

{ material: 'some string' }

为什么会出错