extend express request object with sequelize model using typescript 2 - node.js

Question

I have some models, such as:
import * as Sequelize from 'sequelize'; // !
export interface UserAttributes {
id?: number;
email?: string;
googleToken?: string;
}
export interface UserInstance extends Sequelize.Instance<UserInstance, UserAttributes>, UserAttributes {
}
export interface UserModel extends Sequelize.Model<UserInstance, UserAttributes> {
}
// ... model definition
I need use import statement to use generic type Sequelize.Instance<TInstance, TAttributes>
I wright some middleware to add user instance to request object (or req.session object, doesn't metter)
Then I need typescript to know my new extending, for this I have file src/_extra.ts with content:
/// <reference path="./models/db.ts" /> -- also does not work
declare namespace Express {
export interface Request {
oauthClient: Googleapis.auth.OAuth2; // Googleapis is namespace
user?: UserInstance; // or ContactsProject.Models.UserInstance;
}
export interface Session {/* ... some same */}
}
I need to import my UserInstance type from my model file. Imports break all my _extra namespace definitions, inside namespace I can't use imports.
I have tried create namespace ContactsProject, but I getting same problem: if I use imports, typescript don't see my namespace, if I don't, I cant define my UserInstance type.
Sequelize doesn't declare namespaces.
I just want import some generic type in my namespace.
I use typescript Version 2.0.3.

Answer 1

When you use an import statement in a file, TypeScript treats it as a module. Therefor any namespace you declare inside it will not be global anymore, but local to that module.
Import your interface, and then wrap the namespace declaration in a declare global { ... }.