TypeScript Support

Overview

ReSolve is written in TypeScript and its packages export type declarations for all building blocks of a reSolve application. This article describes how to develop a reSolve application with TypeScript and lists types that you need to use in the application code.

Creating a TypeScript Application

All template and example projects are available both in JavaScript and TypeScript variations. When you use the create-resolve-app tool, add the -t flag to the command input to specify that a TypeScript application should be created:

yarn create resolve-app hello-world-react -e react -t

Developing With reSolve Types

When you develop a reSolve application with TypeScript, you need to assign correct types to all of the application's building blocks (aggregates, read model projections and resolvers, sagas, and so on). Refer to the resources listed below for information on the type scheme that you should follow:

• The Type Correspondence Tables list the available types in a single document section.
• All TypeScript example and template projects are correctly typed and can be used for reference.
• The API Reference articles contain information on the types associated with the described API members.

Example

The code below demonstrates a correctly typed read model implementation:

Projection

import { ReadModel } from '@resolve-js/core'
import { ResolveStore } from '@resolve-js/readmodel-base'
...

const projection: ReadModel<ResolveStore> = {
  Init: async (store) => {
    await store.defineTable('ShoppingLists', {
      indexes: {
        id: 'string',
      },
      fields: ['createdAt', 'name'],
    })
  },

  [SHOPPING_LIST_CREATED]: async (
    store,
    { aggregateId, timestamp, payload: { name } }
  ) => {
    const shoppingList = {
      id: aggregateId,
      name,
      createdAt: timestamp,
    }

    await store.insert('ShoppingLists', shoppingList)
  },
  ...
}
export default projection

Resolvers

import { ReadModelResolvers } from '@resolve-js/core'
import { ResolveStore } from '@resolve-js/readmodel-base'

const resolvers: ReadModelResolvers<ResolveStore> = {
  all: async (store) => {
    return await store.find('ShoppingLists', {}, null, { createdAt: 1 })
  },
}

export default resolvers

For more information on the types used in the above code sample, refer to the following API reference articles:

• ReadModel
• ReadModelResolvers
• ResolveStore

Type Correspondence Tables

The tables below list the available TypeScript types and the packages that export these types.

Write Side

Object	Type	Package
Aggregate Command Handlers	Aggregate	@resolve-js/core
Aggregate Projection	AggregateProjection	@resolve-js/core
Command	Command	@resolve-js/core
Event	Event	@resolve-js/core

Read Side

Read Models

Object	Type	Package
Projection	ReadModel	@resolve-js/core
Resolvers	ReadModelResolvers	@resolve-js/core
Resolver	ReadModelResolver	@resolve-js/core
Store	ResolveStore	@resolve-js/readmodel-base
Query	ReadModelQuery	@resolve-js/core
Query Result	ReadModelQueryResult	@resolve-js/core

View Models

Object	Type	Package
View Model Projection	ViewModelProjection	@resolve-js/core
Read Model Resolvers	ViewModelResolver	@resolve-js/core
Query	ViewModelQuery	@resolve-js/core
Query Result	ViewModelQueryResult	@resolve-js/core

Saga

Object	Type	Package
Saga	Saga	@resolve-js/core

Middleware

Object	Type	Package
Command Middleware	CommandMiddleware	@resolve-js/core
Read Model Projection Middleware	ReadModelProjectionMiddleware	@resolve-js/core
Read Model Resolver Middleware	ReadModelResolverMiddleware	@resolve-js/core

API Handlers

Object	Type	Package
Request	ResolveRequest	@resolve-js/runtime-base
Response	ResolveResponse	@resolve-js/runtime-base
Context	UserBackendResolve	@resolve-js/runtime-base

Monitoring

Object	Type	Package
Metric	MonitoringMetric	@resolve-js/core
Custom Metric	MonitoringCustomMetric	@resolve-js/core
Adapter	MonitoringAdapter	@resolve-js/core
Monitoring Object	Monitoring	@resolve-js/core