mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-02 08:35:07 +08:00
Chris Tate
08115a1d3d
- Share symbol-keyed global caches across statically compiled modules. - Preserve assignment results and evaluation order for native fields, accessors, and nullish defaults. - Read omitted options correctly in specialized JavaScript package calls.
40 lines
1.7 KiB
TypeScript
40 lines
1.7 KiB
TypeScript
let calls = 0;
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function supply(): number { calls++; return 7; }
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let empty: number | undefined;
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let zero: number | undefined = 0;
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console.log(empty ??= supply(), zero ??= supply(), calls);
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const values: (number | undefined)[] = [undefined, 0];
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let indexes = 0;
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function index(): number { indexes++; return 0; }
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console.log(values[index()] ??= supply(), values[index()] ??= supply(), indexes, calls);
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console.log(values[4] ??= supply(), values.length, calls);
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let trace = "";
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class Slot {
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stored: number | null = null;
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get value(): number | null { trace += "get;"; return this.stored; }
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set value(value: number | null) { trace += "set;"; this.stored = value; }
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}
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let slot = new Slot();
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const original = slot;
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function receiver(): Slot { trace += "receiver;"; return slot; }
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function replace(): number { trace += "rhs;"; slot = new Slot(); return 9; }
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console.log(receiver().value ??= replace(), original.stored, slot.stored, trace);
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trace = "";
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console.log(original.value ??= replace(), trace);
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const record: { value?: number } = {};
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console.log(record.value ??= 4, record.value ??= 5);
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let recordGets = 0;
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let recordSets = 0;
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let saved: string | undefined;
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const accessor = {
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get value(): string | undefined { recordGets++; return saved; },
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set value(value: string | undefined) { recordSets++; saved = value; },
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};
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console.log(accessor.value ??= "kept", accessor.value ??= "unused", recordGets, recordSets);
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let absent: undefined;
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let nil: null = null;
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function supplyUndefined(): undefined { trace += "undefined;"; return undefined; }
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function supplyNull(): null { trace += "null;"; return null; }
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trace = "";
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console.log(absent ??= supplyUndefined(), nil ??= supplyNull(), trace);
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