@dandi/common

@dandi/common provides common types and utilities for the rest of the @dandi system.

@dandi/common does not have any dependencies on NodeJS, and therefore can be used on classes shared with projects targeted for the web.

Disposable

The Disposable interface allows implementing classes to define behavior for cleaning up resources like IO streams, database connections, as well as Observable and other event subscriptions.

When used with @dandi/core, Disposable instances are automatically disposed by Dandi at the end of their lifecycle.

class MyService implements Disposable {
  constructor(private dbClient: DbClient) {}

  public dispose(reason: string): void {
    this.dbClient.release()
  }
}

Disposable Utilities

Disposable is also a static class provides several utility functions:

• isDisposable(obj) - Returns true if the object implements dispose(); otherwise, false.

• makeDisposable(obj, disposeFn) - Modifies the specified object to add the provided {@see DisposeFn} as the Disposable.dispose implementation. If the object already has a function member named dispose, it is wrapped and called before the new function.

• use(obj, fn) - Invokes the specified function in a try/catch, statement, then finally disposes the object. Returns the value returned by fn, or rethrows the error thrown by it.

• useAsync(obj, fn) - Same as use, but fn is invoked using await.

• remapDisposed(target, reason) - Overwrites members of the target such that functions and property/field accessors throw an AlreadyDisposedError, a read-only disposed property is set with the value true, and the target is frozen (using Object.freeze) to prevent further modification.