无法在模型实例化时生成唯一的UUIDv4

Question

尝试创建猫鼬模型实例时遇到与UUID相关的问题。

猫鼬模式

export interface IRessourceModel extends IRessource, mongoose.Document { }

export let RessourceSchema: mongoose.Schema = new Schema({
    uuid: {
        type: String,
        default: uuidv4() },
    name: {
        type: String,
        required: true,
        minlength: RessourceValidation.CONSTANTS.NAME_MIN_LENGTH,
        maxlength: RessourceValidation.CONSTANTS.NAME_MAX_LENGTH,
        trim: true,
        validate: {
            validator: RessourceValidation.name,
            message: '{VALUE} is not a valid name'}},
    type: {
        type: String,
        required: true,
        enum: RessourceValidation.ENUM.TYPE,
        validate: {
            validator: RessourceValidation.type,
            message: '{VALUE} is not a valid type'}},
    uploaded: {
        type: Date,
        required: true,
        default: Date.now }
})

export const Ressource: mongoose.Model<IRessourceModel> = mongoose.model<IRessourceModel>('Ressource', RessourceSchema);

实例化

const RessourceModel = mongoose.model('Ressource');
// Some code here...

let Ressource: any = new RessourceModel({
    name: req.body.name,
    type: req.body.type,
})

Ressource.save((err, ressource) => {
    if (err)
        return (APIResponse.jsonErrorAfterMongooseQuery(res, 'Cannot create ressource', err));
    APIResponse.json(res, ressource);
})

---

问题

当我使用上述实例化代码在/ressources/上发送POST请求时，将创建资源，但是，如果我发送另一个POST请求，则创建的第二个资源与UUID相同。第一个...

POST请求1的结果

{
    "type": true,
    "data": {
        "uuid": "1794bbb4-3385-4b0d-909a-e22c60aee608",
        "_id": "5b3a42f5ae71a02af4ed6d11",
        "name": "Name of ressource 1",
        "type": "IMAGE",
        "uploaded": "2018-07-02T15:21:25.866Z",
        "__v": 0
    }
}

POST请求2的结果

{
    "type": true,
    "data": {
        "uuid": "1794bbb4-3385-4b0d-909a-e22c60aee608",
        "_id": "5b3a4530f3ab1f3d40b7ac93",
        "name": "Name of ressource 2",
        "type": "IMAGE",
        "uploaded": "2018-07-02T15:30:56.379Z",
        "__v": 0
    }
}

我错误地使用了default: uuidv4()还是它来自于我模仿猫鼬模型的方式？还是其他？

我确实尝试通过Schema.pre('save')函数设置UUID，但没有成功...

我有点迷茫，感谢您的帮助！

Answer 1

似乎uuidv4()是一个字符串。当然，所有型号都相同。

考虑到这一点：

const uuidv4 = require('uuidv4');

猫鼬default schema option can accept a function产生一个值：

export let RessourceSchema: mongoose.Schema = new Schema({
    uuid: {
        type: String,
        default: uuidv4
    },
    ...