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decorators

const decorators: {
  class: {
     Mixins: (...constructors: any[]) => (derivedCtor: any) => void;
     Singleton: <T>(type: T) => SingletonType;
  };
  function: {
     AsyncSingleExecution: (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
     CacheUntilResolved: (_target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
     Debounce: (delay?: number) => (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
     ImmutableArgs: (_target: any, _propertyKey: string | symbol, descriptor: PropertyDescriptor) => PropertyDescriptor;
     Memoize: (_target: any, _key: string, descriptor: PropertyDescriptor) => void;
     MemoizeAsync: (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
     MemoizeSingleArgPrimitive: <T, R>(_target: any, _propertyKey: string, descriptor: TypedPropertyDescriptor<(...args: any[]) => R>) => TypedPropertyDescriptor<(...args: any[]) => R>;
     QueueTask: (_target: unknown, _key: string, descriptor: PropertyDescriptor) => void;
     RetryAsync: (retries?: number, interval?: number, reThrowException?: boolean) => MethodDecorator;
     Throttle: (delay?: number) => (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
  };
};

Type Declaration​

class​

class: {
  Mixins: (...constructors: any[]) => (derivedCtor: any) => void;
  Singleton: <T>(type: T) => SingletonType;
};

class.Mixins​

Mixins: (...constructors: any[]) => (derivedCtor: any) => void;

A decorator to mix multiple classes into a single class.

Parameters​
constructors​

...any[]

The constructors of the classes to be mixed in.

Returns​

A class decorator that mixes the provided classes into the target class.

(derivedCtor: any) => void

Example​
class A {
  methodA() {
    console.log('A');
  }
}

class B {
  methodB() {
    console.log('B');
  }
}
// Apply decorator
// @Mixins(A, B)
class C {}

const instance = new C();
instance.methodA(); // Outputs: 'A'
instance.methodB(); // Outputs: 'B'

class.Singleton​

Singleton: <T>(type: T) => SingletonType;

A decorator to make a class a singleton.

Type Parameters​
T​

T extends (...args: any[]) => any

Parameters​
type​

T

The class to be made a singleton.

Returns​

SingletonType

A proxy that ensures only one instance of the class is created.

Example​
// @Singleton decorator
class MyClass {
  constructor() {
    console.log('Instance created');
  }
}

const instance1 = new MyClass(); // Outputs: 'Instance created'
const instance2 = new MyClass(); // No output, same instance returned

console.log(instance1 === instance2); // Outputs: true

function​

function: {
  AsyncSingleExecution: (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
  CacheUntilResolved: (_target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
  Debounce: (delay?: number) => (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
  ImmutableArgs: (_target: any, _propertyKey: string | symbol, descriptor: PropertyDescriptor) => PropertyDescriptor;
  Memoize: (_target: any, _key: string, descriptor: PropertyDescriptor) => void;
  MemoizeAsync: (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
  MemoizeSingleArgPrimitive: <T, R>(_target: any, _propertyKey: string, descriptor: TypedPropertyDescriptor<(...args: any[]) => R>) => TypedPropertyDescriptor<(...args: any[]) => R>;
  QueueTask: (_target: unknown, _key: string, descriptor: PropertyDescriptor) => void;
  RetryAsync: (retries?: number, interval?: number, reThrowException?: boolean) => MethodDecorator;
  Throttle: (delay?: number) => (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;
};

function.AsyncSingleExecution​

AsyncSingleExecution: (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;

AsyncSingleExecution decorator ensures that multiple concurrent calls to an async function with the same arguments will return the same promise instance until it resolves. Once resolved, subsequent calls will trigger a new execution.

Parameters​
_target​

any

_propertyKey​

string

descriptor​

PropertyDescriptor

Returns​

PropertyDescriptor

A function that modifies the property descriptor.

Example​
import { AsyncSingleExecution } from './functionDecorators';

class Example {
  @AsyncSingleExecution
  async fetchData(id: number) {
    console.log('Fetching data for', id);
    return new Promise(resolve => setTimeout(() => resolve(id), 1000));
  }
}

const instance = new Example();
const promise1 = instance.fetchData(1);
const promise2 = instance.fetchData(1);

console.log(promise1 === promise2); // true

// Output: // Fetching data for 1 (only logged once)


#### function.CacheUntilResolved

```ts
CacheUntilResolved: (_target: any, propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;

Caches the result of a method until the promise is resolved.

Parameters​
_target​

any

The target object.

propertyKey​

string

The name of the method.

descriptor​

PropertyDescriptor

The property descriptor.

Returns​

PropertyDescriptor

The modified property descriptor.

Example​
class Example {
  // Apply decorator: CacheUntilResolved
  async fetchData() {
    // ...fetch data...
  }
}

function.Debounce​

Debounce: (delay?: number) => (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;

Debounces the method call by the specified delay.

Parameters​
delay?​

number = 300

The delay in milliseconds.

Returns​

A function that modifies the property descriptor.

(_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor

Example​
class Example {
  // Apply decorator: Debounce(500)
  onResize() {
    // ...handle resize...
  }
}

function.ImmutableArgs​

ImmutableArgs: (_target: any, _propertyKey: string | symbol, descriptor: PropertyDescriptor) => PropertyDescriptor;

Makes the arguments of a method immutable.

Parameters​
_target​

any

The target object.

_propertyKey​

string | symbol

The name of the method.

descriptor​

PropertyDescriptor

The property descriptor.

Returns​

PropertyDescriptor

The modified property descriptor.

Example​
class Example {
  // Apply decorator: ImmutableArgs
  updateData(data: any) {
    // ...update data...
  }
}

function.Memoize​

Memoize: (_target: any, _key: string, descriptor: PropertyDescriptor) => void;

Memoizes the result of a method.

Parameters​
_target​

any

The target object.

_key​

string

The name of the method.

descriptor​

PropertyDescriptor

The property descriptor.

Returns​

void

The modified property descriptor.

Example​
class Example {
  // Apply decorator: Memoize
  computeValue(x: number) {
    return x * 2;
  }
}

function.MemoizeAsync​

MemoizeAsync: (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;

Memoizes the result of an async method.

Parameters​
_target​

any

The target object.

_propertyKey​

string

The name of the method.

descriptor​

PropertyDescriptor

The property descriptor.

Returns​

PropertyDescriptor

The modified property descriptor.

Example​
class Example {
  // Apply decorator: MemoizeAsync
  async fetchData() {
    // ...fetch data...
  }
}

function.MemoizeSingleArgPrimitive​

MemoizeSingleArgPrimitive: <T, R>(_target: any, _propertyKey: string, descriptor: TypedPropertyDescriptor<(...args: any[]) => R>) => TypedPropertyDescriptor<(...args: any[]) => R>;

Memoizes the result of a function with a single primitive argument or no arguments. Only caches results for functions that take exactly one primitive argument (string, number, boolean, symbol, null, or undefined) or no arguments at all. Uses a simple object as the cache.

Type Parameters​
T​

T extends string | number | boolean | symbol | null | undefined

R​

R

Parameters​
_target​

any

_propertyKey​

string

descriptor​

TypedPropertyDescriptor<(...args: any[]) => R>

Returns​

TypedPropertyDescriptor<(...args: any[]) => R>

Examples​
// Single primitive argument
class Example {
  // Apply decorator: MemoizeSingleArgPrimitive
  double(x: number) {
    return x * 2;
  }
}
const ex = new Example();
ex.double(2); // Calls original, returns 4
ex.double(2); // Returns cached result, 4
// No arguments
class ExampleNoArg {
  // Apply decorator: MemoizeSingleArgPrimitive
  getRandom() {
    return Math.random();
  }
}
const ex2 = new ExampleNoArg();
ex2.getRandom(); // Calls original, returns a value
ex2.getRandom(); // Returns cached value
// Not cached for non-primitive or multiple arguments
class ExampleObj {
  // Apply decorator: MemoizeSingleArgPrimitive
  sum(obj: { x: number }) {
    return obj.x + 1;
  }
}
const ex3 = new ExampleObj();
ex3.sum({ x: 1 }); // Calls original
ex3.sum({ x: 1 }); // Calls original again (not cached)

function.QueueTask​

QueueTask: (_target: unknown, _key: string, descriptor: PropertyDescriptor) => void;

Queues the method call as a microtask.

Parameters​
_target​

unknown

The target object.

_key​

string

The name of the method.

descriptor​

PropertyDescriptor

The property descriptor.

Returns​

void

The modified property descriptor.

Example​
class Example {
  // Apply decorator: QueueTask
  processTask() {
    // ...process task...
  }
}

function.RetryAsync​

RetryAsync: (retries?: number, interval?: number, reThrowException?: boolean) => MethodDecorator;

Retries an async method a specified number of times with a delay between attempts.

Parameters​
retries?​

number = 3

The number of retry attempts.

interval?​

number = 2000

The delay in milliseconds between retries.

reThrowException?​

boolean = true

Whether to rethrow the exception after all retries fail.

Returns​

MethodDecorator

A method decorator that modifies the property descriptor.

Example​
class Example {
  @RetryAsync(3, 1000, true)
  async fetchData() {
    console.log('Attempting to fetch data...');
    if (Math.random() < 0.7) {
      throw new Error('Fetch failed');
    }
    return 'Data fetched successfully';
  }
}

const instance = new Example();
instance.fetchData().then(console.log).catch(console.error);

// Output (example):
// Attempting to fetch data...
// Attempting to fetch data...
// Attempting to fetch data...
// Error: Fetch failed

function.Throttle​

Throttle: (delay?: number) => (_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor;

Throttles the method call by the specified delay.

Parameters​
delay?​

number = 300

The delay in milliseconds.

Returns​

A function that modifies the property descriptor.

(_target: any, _propertyKey: string, descriptor: PropertyDescriptor) => PropertyDescriptor

Example​
class Example {
  @Throttle(500)
  onScroll() {
    // ...handle scroll...
  }
}