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
46 lines
2.0 KiB
TypeScript
46 lines
2.0 KiB
TypeScript
// Store document state next to transcript entries.
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// Run from packages/durable:
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// node --conditions=source --experimental-strip-types test/examples/01-documents.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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// A document is a JSON object attached to something; here, one per conversation.
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// "rewindable" keeps old values readable, so you can ask what the document
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// looked like when a particular entry was written.
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// `fork` says what a forked copy of the conversation starts with (see 02-forks.ts).
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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", // a fork starts with the value these notes had at the fork entry
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initial: () => ({ text: "" }),
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});
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const chat = await session.commit((tx) => tx.createConversation({ ownership: { kind: "ownerless" } }), context);
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// tx.doc() returns an editable copy of the document (created on first use).
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// Plain assignments to it are saved when the commit finishes.
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const firstEntry = await session.commit(async (tx) => {
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const entry = await tx.appendEntry(chat.id, { kind: "note", data: "hello" });
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(await tx.doc(Notes, chat.id)).text = "after hello";
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return entry;
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}, context);
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const secondEntry = await session.commit(async (tx) => {
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const entry = await tx.appendEntry(chat.id, { kind: "note", data: "goodbye" });
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(await tx.doc(Notes, chat.id)).text = "after goodbye";
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return entry;
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}, context);
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// snapshot() reads the latest value. snapshotAsOf() reads the value that was
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// saved in the same commit as the given entry.
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console.log("latest notes:", await session.snapshot(Notes, chat.id, context));
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console.log("notes at first entry:", await session.snapshotAsOf(Notes, chat.id, firstEntry.id, context));
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console.log("notes at second entry:", await session.snapshotAsOf(Notes, chat.id, secondEntry.id, context));
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await session.close(context);
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