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
54 lines
2.1 KiB
TypeScript
54 lines
2.1 KiB
TypeScript
import { describe, expect, it } from "vitest";
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import { apply, track } from "../src/delta/index.ts";
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describe("tracker ownership", () => {
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it("takes immutable ownership of the imported revision in O(1)", () => {
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const input = {
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point: { x: 3, y: 7, pressure: 0.1 },
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rows: [{ values: [0, false, null, "text", { n: 1 }] }],
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};
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const tracker = track(input);
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expect(tracker.value).toBe(input);
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expect(tracker.value.point).toBe(input.point);
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expect(tracker.value.rows[0]!.values[4]).toBe(input.rows[0]!.values[4]);
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expect(Object.isFrozen(tracker.value.rows[0]!.values)).toBe(false);
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});
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it("preserves null prototypes in an alias-free owned root", () => {
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type Dictionary = { enabled: boolean; child: { n: number } };
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const dictionary = Object.assign(Object.create(null) as Dictionary, { enabled: true, child: { n: 1 } });
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const tracker = track({ dictionary, left: { nested: [{ n: 1 }] }, right: { nested: [{ n: 1 }] } });
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expect(Object.getPrototypeOf(tracker.value.dictionary)).toBeNull();
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expect(tracker.value.dictionary).toBe(dictionary);
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expect(tracker.value.left).not.toBe(tracker.value.right);
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expect(tracker.value.left.nested[0]).not.toBe(tracker.value.right.nested[0]);
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});
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it("does not traverse a trusted root while taking ownership", () => {
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let reads = 0;
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const input = Object.defineProperty({}, "untrustedAccessor", {
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enumerable: true,
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get() {
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reads += 1;
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throw new Error("root was traversed");
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},
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});
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const tracker = track(input);
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expect(tracker.value).toBe(input);
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expect(reads).toBe(0);
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});
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it("copies assigned and inserted values immediately", () => {
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const tracker = track({ rows: [] as { nested: { value: number } }[] });
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const assigned = { nested: { value: 1 } };
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const change = tracker.beginChange();
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change.state.rows.push(assigned);
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assigned.nested.value = 9;
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expect(change.state.rows[0]!.nested.value).toBe(1);
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const prepared = change.prepare();
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expect(prepared.value.rows[0]!.nested.value).toBe(1);
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const replica = apply(structuredClone(prepared.base), prepared.ops);
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expect(replica).toEqual(prepared.value);
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});
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});
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