Mongoose 5.x.x创建Schema是否需new关键字？文档存在矛盾

Great question—this inconsistency across the Mongoose docs is definitely confusing, especially if you’re coming from Mongoose 4.x where using new was mandatory. Let’s break this down clearly:

• Short answer: No, you don’t have to use the new keyword with mongoose.Schema() in Mongoose 5.x. Both syntaxes work perfectly and produce valid Schema instances.
• Longer explanation: Mongoose 5.x updated the Schema constructor to act as a factory function when called without new. That means both:

  var kittySchema = mongoose.Schema({ name: String });
  

  and

  var kittySchema = new mongoose.Schema({ name: String });
  

  will create identical, functional Schema objects under the hood.

The mixed syntax in the docs is likely due to incremental updates across different sections. The Quick Start and homepage were probably updated first to showcase the simpler, new-less syntax, while the dedicated Schemas section retained the older (still valid) new syntax temporarily during the transition.

Quick verification #

If you test both approaches in a Mongoose 5.x environment, you’ll find that kittySchema instanceof mongoose.Schema returns true for both cases—confirming they’re the same type of instance.

Recommendation #

While both styles are valid, it’s best to pick one and stick with it for consistency in your codebase. If you’re working on an existing project that uses new, keep following that pattern. If you’re starting fresh, the new-less syntax is a bit cleaner and aligns with the newer examples in the docs.

内容的提问来源于stack exchange，提问作者Cazineer