CloudControl Pro 9 Docs / lang

lang

lang provides language-related API, such as delay.

Table of contents

Classes

• Deferred
• TimeoutError

Interfaces

• ReadOnlyProperty

Functions

• delay
• lazy
• lazyProp
• promise

Functions

delay

▸ delay(timeout): Promise<void>

Returns a Promise, which will resolve after timeout. For example, await delay(1000) will resolve after 1 second. This function does not block the thread/event loop.

Example

"nodejs";
const { delay } = require('lang');
async function main() {
  console.log(1);
  await delay(2000);
  console.log(2);
}
main();

Parameters

Name	Type	Description
timeout	number	timeout, if less than or equal to 0, then the function returns a Promise that resolves immediately.

Returns

Promise<void>

---

lazy

▸ lazy(target, name, __namedParameters?): any

TypeScript decorator, which cannot be used in JavaScript.

Decorates class's getter properties, and the decorated properties will be automatically executed and saved the value on the first call, and then use the saved value on subsequent calls.

Example

import { lazy } from 'lang'

class Sum {
   private n: number;

   constructor(n: number) {
     this.n = n;
   }

   @lazy
   get sum() {
     console.log('calculating sum...');
     let result = 0;
     for (let i = 0; i < this.n; i++) {
          result += i;
     }
     return result;
   }
}

const sum = new Sum(10);
console.log(sum.sum); // calculating sum...55
console.log(sum.sum); // 55

Parameters

Name	Type
target	any
name	string
__namedParameters	PropertyDescriptor

Returns

any

---

lazyProp

▸ lazyProp<T>(evaluator): ReadOnlyProperty<T>

Type parameters

Name
T

Parameters

Name	Type
evaluator	() => T

Returns

ReadOnlyProperty<T>

---

promise

▸ promise<T>(executor): Promise<T>

Creates a Promise, which is similar to new Promise, but it will keep the engine running when the Promise is in the pending state (before resolve/reject).

Because nodejs does not know the asynchronous behavior of Java APIs, this function is usually used to create a Promise for a Java API, and keep the engine running until the Java API returns.

Example

"nodejs";
const { promise } = require('lang');
const { android } = require('android');

function loadAudioAsync(file) {
  const SoundPool = android.media.SoundPool;
  return promise(function (resolve) {
     const soundPool = new SoundPool(1, SoundPool.STREAM_MUSIC, 0);
     soundPool.setOnLoadCompleteListener($autojs.java.wrap(() => resolve(soundPool)));
     soundPool.load(file, 1);
  });
}

Type parameters

Name
T

Parameters

Name	Type
executor	(resolve: (value: T | PromiseLike<T>) => void, reject: (reason?: any) => void) => void

Returns

Promise<T>