mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-02 08:35:07 +08:00
Chris Tate
057ac2cea2
- 2530-2535 and 2541 lock in the destructuring forms the static tier already compiled but the corpus never pinned: object/array/tuple declarations (renames, defaults, holes, nesting, fresh rest tails), the options-object parameter pattern (element and whole-pattern defaults, tuple/rest parameter patterns), for-of heads (containers, defaults, rest, existing bindings), object rest freshness and key order, assignment basics (swaps, chains, expression value), and evaluation order (RHS once, elements left to right, lazy defaults that see earlier bindings). - All byte-identical against Node under both backends, and each reports 100% static coverage.
46 lines
1.5 KiB
TypeScript
46 lines
1.5 KiB
TypeScript
// Array and tuple destructuring in declarations: holes, defaults (with
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// the bounds test JS's past-the-end undefined demands), rest packing a
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// fresh tail, tuple positions as field reads, nested patterns.
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const arr = [10, 20, 30];
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const [e0, e1] = arr;
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const [, , e2] = arr;
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console.log(e0, e1, e2);
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// Defaults fire past the end and on in-bounds undefined — never on null.
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const short: number[] = [7];
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const [f0 = -1, f1 = -2, f2 = -3] = short;
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console.log(f0, f1, f2);
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const withUndef: (number | undefined)[] = [undefined, 5];
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const [g0 = 100, g1 = 200] = withUndef;
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console.log(g0, g1);
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// Rest packs a FRESH tail copy: mutating it never reaches the source.
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const [head, ...tail] = arr;
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tail[0] = 999;
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console.log(head, tail.join(","), arr.join(","));
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// Tuples: positional field reads, defaults, rest tails.
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const tup: [number, string, boolean] = [1, "s", true];
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const [t0, t1, t2] = tup;
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console.log(t0, t1, t2);
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const pair: [number, string] = [8, "y"];
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const [p0, ...pRest] = pair;
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console.log(p0, pRest[0]);
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// Nested array patterns recurse.
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const grid: [number, [number, number]] = [1, [2, 3]];
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const [g, [x1, y1]] = grid;
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console.log(g, x1, y1);
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// Mixed nesting: records inside tuples inside arrays.
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const rows: [string, { n: number }][] = [["a", { n: 1 }], ["b", { n: 2 }]];
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const [[label0, { n: n0 }], [label1, { n: n1 }]] = rows;
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console.log(label0, n0, label1, n1);
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// Empty patterns are pure no-ops past the source's own evaluation.
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const [] = arr;
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const {} = tup;
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console.log("done");
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