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;

Parameters

derivedCtor

any

Returns

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;

Parameters

_target

any

_propertyKey

string

descriptor

PropertyDescriptor

Returns

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

The name of the method.

string | symbol

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;

Parameters

_target

any

_propertyKey

string

descriptor

PropertyDescriptor

Returns

PropertyDescriptor

Example

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