Create Your First Service

A service encapsulates business logic and keeps controllers clean.

Create UserService

Create src/service/user.service.ts:

import { Provide } from '@midwayjs/core';

@Provide()
export class UserService {
  private users = [
    { id: 1, name: 'Tom', email: '[email protected]' },
    { id: 2, name: 'Jerry', email: '[email protected]' },
    { id: 3, name: 'Kate', email: '[email protected]' },
  ];

  async getUsers() {
    return this.users;
  }

  async getUserById(id: number) {
    return this.users.find(user => user.id === id);
  }

  async createUser(name: string, email: string) {
    const newUser = {
      id: this.users.length + 1,
      name,
      email,
    };
    this.users.push(newUser);
    return newUser;
  }
}

Key points

@Provide()

Registers this class into the IoC container.

Service responsibility

Service should:

• hold business logic
• call databases/APIs
• transform data

Service should not:

• handle HTTP routing directly
• depend on ctx for request flow

Async-first style

Service methods are usually async because real apps call I/O resources.

Summary

• Register service with @Provide()
• Keep business logic in service layer
• Prefer async methods for consistency