Using ES6 Promises in Mongoose code

Question

I am trying to use ES6 Promises for Mongoose ODM in TypeScrpt.

I have the following line

mongoose.Promise = Promise;

Which give me the following error:

error TS2322: Type 'PromiseConstructor' is not assignable to type 'typeof Promise'.
  Type 'Promise<any>' is not assignable to type 'Promise<any>'.
    Property 'end' is missing in type 'Promise<any>'.

Answer 1

You are assigning the ES6 Native promise to mongoose promise:

mongoose.Promise = Promise;

You get the error

Property 'end' is missing in type 'Promise'.

Because the native Promise is missing the property end which is present in mongoose Promise (docs https://www.npmjs.com/package/mpromise).

Workaround

You can either:

• Hack the mongoose definition to lie and say its a ES6 Promise instead of mpromise

• Or Suppress the error:

  mongoose.Promise = Promise as any;
  

• Or not do this entirely :)