liu yang

Posted on Jun 15

Youdaoplaceholder0 HarmonyOS Next Development Language and Tools

#harmonyosnext

I.HarmonyOS Next Development Language: The Advanced Evolution of TypeScript/JavaScript

1. ArkTS 3.0: The Super Extension of TypeScript

Core Positioning: A strongly - typed language designed for HarmonyOS Next, based on TypeScript 5.3+ specifications, with added distributed - capability annotations and hardware - abstraction syntax.
Comparison with JavaScript/TS:

Feature	JavaScript	TypeScript	ArkTS 3.0
Type Checking	Weakly - typed	Statically - typed	Enhanced runtime - type
Distributed Annotations	Not supported	Requires third - party libraries	Native @Remote support
UI Description	JSX	TSX	Declarative syntax chain calls
Hardware API Calls	Wrapped libraries	Type declarations	Native device - awareness

Code Example: Cross - Device Service Calls

// Calling a smartwatch's heart rate sensor (ArkTS syntax)  
import sensor from '@ohos.sensor.distributed';  

@Remote // Marked as callable across devices  
class HeartRateMonitor {  
@Watch("heartRate")  
heartRate: number = 0;  

  startMonitoring() {  
sensor.on('heartRate', (data) => {  
  this.heartRate = data.value;  
});  
  }  
}  

// Calling from a phone  
let watchService = new RemoteService('wearable_001');  
watchService.callMethod('startMonitoring');

II.Deveco Studio 4.2: Essential Features for Efficient Development

1. Intelligent Code Assistant (AI Coding Partner)

Feature Highlights:
- Context - aware Completion: Typing @Sta automatically associates with @State variables.
- Code Defect Scanning: Real - time detection of memory - leak risks (e.g., unreleased distributed handles).

Operation Demonstration:

// Automatically generates a distributed data request template when typing "fetch"  
fetch('@ohos.net.http')  
  .setHeader('Content-Type', 'application/json')  
  .request<{ data: string }>()  
  .then(response => { /*...*/ });

2. Multi - device Live Preview 2.0

Use Scenarios:
- One - click Multi - screen Preview: Preview UI adaptation for phones, tablets, and in - car systems simultaneously.
- State Hot Injection: Directly modify @State variable values in the preview interface for testing responses.

III.Migration Guide for TypeScript/JavaScript

1. Adapting Existing TS/JS Projects

Instructions:
- Install the Adaptation Plugin:
```
  npm install hmos-next-migrate --save-dev
```
- Syntax Conversion:
```
  npx hmos-migrate ./src --target arkts
```
- Annotation Completion: Automatically adds decorators like @Entry and @Component.

2. Hybrid Development Mode

Applicable Scenarios: Calling old modules during gradual migration.

// Calling a legacy JS module in ArkTS  
import legacyModule from '../js/oldModule.js';  

@Entry  
@Component  
struct HybridPage {  
  build() {  
    Column() {  
      Button('Call JS Method')  
        .onClick(() => {  
          legacyModule.deprecatedFunction(); // Logs a warning in the console  
        })  
    }  
  }  
}

IV.Tips for Improving Development Efficiency

1. Shortcut Keys (Windows/Mac)

Function	Shortcut Key
Quickly Generate UI Skeleton	Ctrl + Alt + U
Distributed Service Template	Ctrl + Shift + R
Device Switching	Ctrl + D

2. Custom Code Templates

Configuration Path: File → Settings → Editor → Live Templates → HarmonyOS

Example Template:

// Input "dservice" to generate a distributed service template  
@Remote  
class $ServiceName$ {  
  $METHODS$  
}

Conclusion: In 2025, HarmonyOS Next, through the deep collaboration of the ArkTS language and the DevEco Studio toolchain, offers developers an efficient and intuitive distributed application development experience. Whether migrating from the TypeScript/JavaScript ecosystem or directly developing next - generation atomic services, developers can truly experience the charm of "develop once, deploy across multiple devices."

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