ya-syn

ya-syn

Yet Another Synchronizer for TypeScript.

• Promise based synchronization
• Concurrency setting to support lock(n==1) and semaphore(n>1)
• Reentrant synchronization (nodejs only at this point)
• Timeout
• Throttling
• Logging

stateDiagram-v2
    direction LR
    [*] --> Acquire
    [*] --> Throttle
    Acquire --> Timeout
    Acquire --> Acquired
    state Synchronized {
        Acquired --> Release
        state Reenter {
            direction LR
            Enter --> Exit
        }
    }
    Release --> Finish
    [*] --> Enter
    Exit --> Finish
    Finish --> [*]

How to install

npm install ya-syn

Use cases

• Please check test/samples for all the use cases

Use case: Global Synchronizer Provider

• It is recommended to create global synchronizer provider to configure ids and logging in one place.

Use case: Lock

• Simple reentrant lock. concurrency == 1

Use case: Semaphore

• Simple reentrant semaphore. concurrency > 1

Use case: Class Synchronizer

• You can obtain synchronizer for given class

Use case: Instance Synchronizer

• You can obtain synchronizer for given class
• Synchroinzer provider keeps weak ref to the key object. When the object get freed, synchronizer instance will be freed too

Use case: Key Synchronizer

• synchronizer provider keeps string to synchronizer map
  • Note: This mapping is not weak reference.
• You can nest multiple synchronizer
  • Main synchronizer to limit number of concurrent requests to 3
  • Per host synchronizer to limit number of concurrent requests to same host to 1

Use case: CacheProvider

• Object cache with asynchronous factory callback
• You can specify default TTL
• You can override ttl when you get cache

Use case: TaskExecutor

• Execute task in parallel using asynchronous generator pattern

Use case: mergeGenerators

• utility function to merge multiple asynchronous generator into one
• TaskExecutor can process multiple async generators using mergeGenerators

Other useful components

LazyInitializer

• Provider class with asynchronous factory callback.

Use case: Async Singleton

• You can create top level singleton instance with asynchronous initialization
• factory method is called only once

Use case: Async Instance Variable

• You can create instance variable which require asynchronous initialization.

Use case: Async Class Variable

• You can create class variable which require asynchronous initialization.

Version History

• 1.6.0
  • Add WeakIndexMap
• 1.5.0
  • Add Process Monitor
• 1.4.2
  • Fix bug in waitCompleteAll
• 1.4.1
  • Fix resource leak in reentrant check
• 1.4.0
  • Add waitComplete/waitCompleteAll handlers to CoreSemaphore
  • Restructure task executor by replace Synchronizer with CoreSemaphore
• 1.3.4
  • Update Core Semaphore method signature
• 1.3.3
  • Expose Core Semaphore
• 1.3.2
  • Reduce memory usage
• 1.3.1
  • Add eager option to LazyInitializer
  • Fix bug that executor doesn't wait until all tasks completes
• 1.3.0
  • Add mergeAsyncGenerators to enhance task executor
• 1.2.0
  • Added Task Executor
• 1.1.2
  • Use weak ref for string key based synchronizer provider
  • Set default provider/synchronizer/execution id to uuid
• 1.1.1
  • Fix bug in handling reenter with throttling
• 1.1.0
  • Add capture utility method to CachedProvider(#5)
  • Add reentrant entry detector to LazyInitializer(#3)
• 1.0.1
  • Fix event handling leak
• 1.0.0
  • Initial Release

Next Step

• Support reentrant synchronization on web browser

License

This project is under the MIT license. Copyright (c) 2024 Tomohisa Ota