我的node项目原来是好的，后来我不记得我做了什么加载mongodb依赖报错了
就这一句
var MongoClient = require('mongodb').MongoClient;
报的错:
发生异常: Error
Error: ENOENT: no such file or directory, access 'e:\test\node_modules\require_optional\index.js/package.json'

at Object.fs.accessSync (fs.js:214:3)
at fs.existsSync (fs.js:247:8)
at find_package_json (e:\test\node_modules\require_optional\index.js:14:9)
at find_package_json_with_name (e:\test\node_modules\require_optional\index.js:34:20)
at require_optional (e:\test\node_modules\require_optional\index.js:69:13)
at Object.<anonymous> (e:\test\node_modules\mongodb-core\index.js:8:20)
at Module._compile (internal/modules/cjs/loader.js:678:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
at Module.load (internal/modules/cjs/loader.js:589:32)
at tryModuleLoad (internal/modules/cjs/loader.js:528:12)