API reference › @evolu/common › Resource

Concurrency-safe helpers for efficient reuse and replacement of disposable resources.

Replacement policies

Replacing a live resource has two policies.

Exclusive replacement disposes the current resource and then creates the next, so at most one exists and there is an observable gap with none. ResettableResource implements it. Leases do not fit this policy: a reset is requested precisely when holders are stuck on a dead resource, so waiting for them inverts the purpose, and revoking them is safe only when the resource's own API is total after disposal, in which case a lease adds nothing.

Overlapping replacement creates the next generation first and disposes the previous one when its last lease is released, so work in progress finishes on the generation it started with. It keeps the old generation when creation fails, at the cost of both existing for a while. It is not implemented. It belongs on SharedResource as an invalidate operation: mark the current generation stale, stop leasing it, dispose it on its last release, and create the next on the next acquire. Before that can ship, SharedResourceByKey must stop removing a key when its resource is disposed, and SharedResourceByKeyWithClaims must stop keeping one resource object per key for the lifetime of its claims.

Functions

Function	Description
createResettableResource	Creates ResettableResource.
createSharedResource	Creates SharedResource.
createSharedResourceByKey	Creates SharedResourceByKey.
createSharedResourceByKeyWithClaims	Creates SharedResourceByKeyWithClaims.

Interfaces

Interface	Description
ClaimLease	An owned lease on the resource-retains added by one claim operation.
Lease	An owned lease on a shared Resource.
ResettableResource	A Resource reset in place.
SharedResource	Shared Resource.
SharedResourceByKey	Shared Resources keyed by logical identity.
SharedResourceByKeyOptions	Options for createSharedResourceByKey.
SharedResourceByKeySnapshot	Snapshot returned by SharedResourceByKey.snapshot.
SharedResourceByKeyWithClaims	Shared keyed Resources retained through claims.
SharedResourceByKeyWithClaimsOptions	Options for createSharedResourceByKeyWithClaims.
SharedResourceByKeyWithClaimsSnapshot	Snapshot returned by SharedResourceByKeyWithClaims.snapshot.
SharedResourceOptions	Options for createSharedResource.
SharedResourceSnapshot	Snapshot returned by SharedResource.snapshot.

Type Aliases

Type Alias	Description
BorrowedResource	Borrowed Resource.
Resource	Disposable resource.