Application Configuration

This lesson follows the env_config document and focuses on practical multi-environment setup.

Config file conventions

src/config/
  config.default.ts
  config.local.ts
  config.prod.ts
  • config.default.ts: loaded in all environments
  • config.{env}.ts: loaded only for a specific environment and overrides defaults
import { MidwayConfig } from '@midwayjs/core';


export default {
  koa: {
    keys: ['123456'],
    port: 7001,
  },
  app: {
    name: 'midway-tutorial',
    version: '1.0.0',
  },
} as MidwayConfig;

Load config in configuration.ts

import { Configuration } from '@midwayjs/core';
import * as DefaultConfig from './config/config.default';
import * as LocalConfig from './config/config.local';


@Configuration({
  importConfigs: [
    {
      default: DefaultConfig,
      local: LocalConfig,
    },
  ],
})
export class MainConfiguration {}

Quick verification

Update src/config/config.default.ts:

app: {
  name: 'midway-learning-lab',
  version: '2026.02',
},

After save:

  • output should show app restart
  • Preview remains available on port 7001
  • GET / should return updated config values

Read config in code

import { Controller, Get, Config } from '@midwayjs/core';


@Controller('/')
export class HomeController {
  @Config('app.name')
  appName: string;


  @Config('app.version')
  appVersion: string;


  @Get('/')
  async home() {
    return {
      name: this.appName,
      version: this.appVersion,
    };
  }
}

Summary

  • Use config.default.ts + config.{env}.ts
  • Prefer object-based config exports
  • Declare env config explicitly in importConfigs
  • Override behavior follows later-layer precedence
Middleware Basics
Data Validation
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Preparing Environment
  • npm install
  • npm run dev