holdReader

Lets a pending read inside a transition keep the boundary's content: when the tracker's hold() returns true (the boundary holds its content for the transition), the reader throws SUSPENSION and keeps its previous value until the boundary wakes it. Call it from a data primitive's reader when its data is pending, the reader is tracked and inTransition is true, as useResource does. Does nothing before the transition machinery exists, or when the tracker has no hold.

Import#

import { holdReader } from "@shadow-js/core/extend";

Signature#

function holdReader(tracker: { hold?(): boolean }): void

Parameters#

Throws#

• SUSPENSION (not an error) when the boundary holds its content.

Examples#

import { useContext, SuspenseContext } from "@shadow-js/core";
import { currentListener, holdReader, inTransition } from "@shadow-js/core/extend";

export function readPending(): void {
  const tracker = useContext(SuspenseContext);
  if (tracker !== null && currentListener() !== null && inTransition()) holdReader(tracker);
}