alexion
6081e3e325
Imported as a linear vendor commit so forge rebases do not replay the upstream root tree. git-subtree-dir: third_party/pi git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0
42 lines
1.5 KiB
TypeScript
42 lines
1.5 KiB
TypeScript
// Serialize asynchronous document work with a watch.
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// Run from packages/durable:
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// node --conditions=source --experimental-strip-types test/examples/05-watches.ts
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import { BACKGROUND_CONTEXT } from "@earendil-works/chord/context";
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import { createSession, defineDoc, MemoryStorage } from "../../src/index.ts";
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const context = BACKGROUND_CONTEXT;
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const session = createSession(new MemoryStorage());
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const Notes = defineDoc<{ text: string }>({
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kind: "example.notes",
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version: 1,
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scope: "conversation",
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history: "rewindable",
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fork: "asOf",
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initial: () => ({ text: "" }),
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});
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const chat = await session.commit(async (tx) => {
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const conversation = await tx.createConversation({ ownership: { kind: "ownerless" } });
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(await tx.doc(Notes, conversation.id)).text = "first";
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return conversation;
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}, context);
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// A watch starts from one stable acquisition revision. Slow callbacks never
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// overlap; exact committed frames buffer, with a full-value reset after 100.
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const notesWatch = await session.watchDoc(Notes, chat.id, context);
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if (notesWatch === undefined) throw new Error("notes are absent");
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console.log("watch baseline:", notesWatch.value);
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const delivered = new Promise<void>((resolve) => {
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notesWatch.start(async (value, _ops, _deliveryContext) => {
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console.log("watch update:", value);
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resolve();
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});
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});
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await session.commit(async (tx) => {
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(await tx.doc(Notes, chat.id)).text = "observed asynchronously";
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}, context);
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await delivered;
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await notesWatch.stop();
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await session.close(context);
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