Mongoose Mongo DB使用NodeJs错误：抛出新的TypeError（'未定义类型在`'+ path +

Question

我在下面的代码中添加'content Binary Data下面的那一刻我收到以下错误。我缺少什么

代码

var mongoose = require('mongoose'),
    Schema = mongoose.Schema;

var MeterdataSchema = new Schema({
  serialno: String,
  info: String,
  active: Boolean,
  content: "Binary Data"
});

module.exports = mongoose.model('Meterdata', MeterdataSchema);

错误

>> Waiting for server reload...
D:\Users\rohanindotech\Developer\yoangfull2\node_modules\mongoose\lib\schema.js:
362
    throw new TypeError('Undefined type at `' + path +
          ^
TypeError: Undefined type at `content`
  Did you try nesting Schemas? You can only nest using refs or arrays.
    at Function.Schema.interpretAsType (D:\Users\rohanindotech\Developer\yoangfu
ll2\node_modules\mongoose\lib\schema.js:362:11)
    at Schema.path (D:\Users\rohanindotech\Developer\yoangfull2\node_modules\mon
goose\lib\schema.js:305:29)
    at Schema.add (D:\Users\rohanindotech\Developer\yoangfull2\node_modules\mong
oose\lib\schema.js:217:12)
    at new Schema (D:\Users\rohanindotech\Developer\yoangfull2\node_modules\mong
oose\lib\schema.js:73:10)
    at Object.<anonymous> (D:\Users\rohanindotech\Developer\yoangfull2\server\ap
i\meterdata\meterdata.model.js:6:23)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
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