mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-23 06:10:02 +08:00
Chris Tate
3f51c72ae8
- Construct Sets from live collection iterators while preserving order and reference identity. - Reject checked key conversions that would copy existing references. - Avoid repeated compiler traversal and cache-validation reads.
60 lines
2.4 KiB
TypeScript
60 lines
2.4 KiB
TypeScript
const source = new Map<string, number>([["a", 1], ["b", 2], ["c", 2]]);
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const readonlySource: ReadonlyMap<string, number> = source;
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console.log("keys", [...new Set(readonlySource.keys())].join(","));
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console.log("values", [...new Set(source.values())].join(","));
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// Construction consumes the remaining live cursor and exhausts every alias.
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const cursor = source.keys();
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const alias = cursor;
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console.log("first", cursor.next().value);
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source.delete("b");
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source.set("d", 4);
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source.set("b", 5);
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console.log("remaining", [...new Set(alias)].join(","));
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source.set("e", 6);
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console.log("done", cursor.next().done, new Set(cursor).size);
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const cleared = source.values();
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console.log("before clear", cleared.next().value);
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source.clear();
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source.set("fresh", 7);
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console.log("after clear", [...new Set(cleared)].join(","));
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const empty = new Map<string, number>();
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const pending = empty.values();
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empty.set("added", 8);
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console.log("pending", [...new Set(pending)].join(","));
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const exhausted = empty.keys();
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console.log("exhaust", new Set(exhausted).size);
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empty.set("later", 9);
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console.log("still done", new Set(exhausted).size);
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let calls = 0;
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function makeCursor(): SetIterator<string> {
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calls++;
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return new Set<string>(["red", "green", "red"]).values();
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}
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console.log("temporary", [...new Set(makeCursor())].join(","), calls);
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const set = new Set<string>(["x", "y"]);
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const readonlySet: ReadonlySet<string> = set;
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console.log("set keys", [...new Set(readonlySet.keys())].join(","));
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const setCursor = set.values();
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console.log("set first", setCursor.next().value);
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set.delete("y");
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set.add("z");
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console.log("set rest", [...new Set(setCursor)].join(","), setCursor.next().done);
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const numbers = new Map<string, number>([["n1", NaN], ["n2", NaN], ["minus", -0], ["plus", 0]]);
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const unique = new Set(numbers.values());
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console.log("same value", unique.size, unique.has(NaN), unique.has(-0));
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for (const value of unique) console.log("canonical", Number.isNaN(value), Object.is(value, -0));
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const left = new Map<string, number>([["left", 1]]);
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const right = new Set<string>(["right"]);
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const chooseLeft = calls === 1;
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console.log("conditional", [...new Set(chooseLeft ? left.keys() : right.values())].join(","));
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const checked = new Map<string, unknown>([["number", 1], ["text", "1"], ["duplicate", 1]]);
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const checkedSet = new Set(checked.values());
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console.log("checked", checkedSet.size, checkedSet.has(1), checkedSet.has("1"));
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