在与Mongoostic同步模型时，我收到以下错误：

TypeError：无法读取属性'toLowerCase'的未定义在setIndexNameIfUnset（/app/node_modules/mongoosastic/lib/mongoosastic.js:239： 29）在EmbeddedDocument.schema索引[作为索引]（/app/node_modules/mongoosastic/lib/mongoosastic.js:385： 5）在EmbeddedDocument.post保存（/app/node_modules/mongoosastic/lib/mongoosastic.js:269： 14）在下一个（/app/node_modules/kareem/index.js:198： 31）在Kareem.execPost（/app/node_modules/kareem/index.js:217： 3）在 /app/node_modules/mongoose/lib/plugins/saveSubdocs.js:54：29在每（/app/node_modules/猫鼬/lib/助手/each.js:11： 5）在模型。/app/node_modules/kareem/index.js:193： 9）在下一个（/app/node_modules/kareem/index.js:212： 9）在Kareem.execPost（/app/node_modules/kareem/index.js:217： 3）在_cb（/app/node_modules/kareem/index.js:307： 15）在 /app/node_modules/mongoose/lib/model.js:400： 5在 /app/node_modules/mongoose/lib/model.js:324： 11在运行微任务（）

1.）orderLineItem模式：

let orderLineItemSchema = new mongodb.Schema({
    orderId: { type: String, es_indexed: true },
    name: { type: String, es_indexed: true },
    description: { type: String, es_indexed: true },
    privateNotice: { type: String, es_indexed: true },
    netPrice: { type: String, default: 0, es_indexed: true },
    taxPercent: { type: Number, default: 23, es_indexed: true },
    projectFile: { type: projectFileSchema, es_schema: projectFileSchema, es_indexed: true, es_type: 'nested', es_include_in_parent: true },
    component: { type: [componentSchema], es_indexed: true, es_type: 'nested', es_include_in_parent: true },
    additionalFiles: { type: [projectFileSchema], es_indexed: true, es_type: 'nested', es_include_in_parent: true },
    status: { type: orderLineItemStatusSchema, es_indexed: true },
    accepted: { type: Boolean, default: false, es_indexed: true },
    archived: { type: Boolean, default: false, es_indexed: true }
}, {
    timestamps: true
});

2.

let projectFileSchema = new mongodb.Schema({
    name: { type: String, es_indexed: true },
    mimeType: { type: String, es_indexed: true },
    path: { type: String, es_indexed: true },
    archived: { type: Boolean, default: false, es_indexed: true }
});

3.）组件模式：

let componentSchema = new mongodb.Schema({
    name: { type: String, es_indexed: true },
    category: { type: String, es_indexed: true },
    componentId: { type: String, es_indexed: true },
    symbol: { type: String, es_indexed: true },
    archived: { type: Boolean, default: false, es_indexed: true }
});

4.）orderLineItemStatusSchema：

let orderLineItemStatusSchema = new mongodb.Schema({
    name: {
        type: String,
        default: 'Utworzony'
    }
}, {
    timestamps: true
});

5.）我的同步代码：

const synchronize = (model) => {
    let stream = model.synchronize();

    stream.on('data', function(err, doc){
      // Logging success to the console
    });
    stream.on('close', function(){
      // Logging ...
    });
    stream.on('error', function(err){
        console.log(err);
    });
}

module.exports = synchronize;

6.）以下是我如何使用它：

const mongodb = require('mongoose');
const mtastic = require('mongoosastic');
const esClient = require('../dependencies/elasticsearch');
const orderLineItemSchema = require('../schemas/OrderLineItem/OrderLineItem');
const synchronizer = require('../helpers/synchronizer'); // This is the synchronization function

orderLineItemSchema.plugin(mtastic, {
    esClient: esClient
});

let OrderLineItem = mongodb.model('OrderLineItem', orderLineItemSchema);

let interval = setInterval(() => {
    synchronizer(OrderLineItem);
}, 10000);

module.exports = OrderLineItem;

这与我在应用程序中同步其他模型的方式完全相同，但只有这个模型返回该错误。

我怎样才能解决这个问题？