猫鼬：自定义架构类型

我遵循了有关自定义架构类型的猫鼬文档，以创建“大字符串”：

"use strict";

const mongoose = require('mongoose')

let STRING_LARGE = (key, options) => {   
  mongoose.SchemaType.call(this, key, options, 'STRING_LARGE'); 
}; 
STRING_LARGE.prototype = Object.create(mongoose.SchemaType.prototype);

STRING_LARGE.prototype.cast = function(val) {   
  let _val = String(val);   
  if(!/^[a-zA-Z0-9]{0,400}$/.test(_val)){
    throw new Error('STRING_LARGE: ' + val + ' is not a valid STRING_LARGE');   
  }

  return _val; };

module.exports = STRING_LARGE;

我在架构中像这样使用它：

"use strict";

const mongoose = require('mongoose');

mongoose.Schema.Types.STRING_LARGE = require('./types/string_large')

const schema = new mongoose.Schema({
  details:     { type: STRING_LARGE, required: true },
  link:        { type: STRING_LARGE, required: true }
});

module.exports = schema;

但是我得到了错误：

[path] \ schemas [shema.js]：8
详细信息：{类型：STRING_LARGE，必填：true}，

ReferenceError：在对象上未定义STRING_LARGE。（[路径] \ schemas [shema.js]：8：24）...

--------------------------更新：工作代码-------------------- ------

使用“功能（）”代替“（）=>”

"use strict";

const mongoose = require('mongoose')

function STRING_LARGE (key, options) {   
  mongoose.SchemaType.call(this, key, options, 'STRING_LARGE'); 
}; 
STRING_LARGE.prototype = Object.create(mongoose.SchemaType.prototype);

STRING_LARGE.prototype.cast = function(val) {   
  let _val = String(val);   
  if(!/^[a-zA-Z0-9]{0,400}$/.test(_val)){
    throw new Error('STRING_LARGE: ' + val + ' is not a valid STRING_LARGE');   
  }

  return _val; };

使用“ mongoose.Schema.Types.LARGE_STRING”而不是“ LARGE_STRING”

module.exports = STRING_LARGE;

"use strict";

const mongoose = require('mongoose');

mongoose.Schema.Types.STRING_LARGE = require('./types/string_large')

const schema = new mongoose.Schema({
  details:     { type: mongoose.Schema.Types.STRING_LARGE, required: true },
  link:        { type: mongoose.Schema.Types.STRING_LARGE, required: true }
});

module.exports = schema;