mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-24 06:14:01 +08:00
Chris Tate
b3217f0650
In TypeScript, Object.values over a checked-dynamic value whose result is only iterated with for-of, indexed, or passed to every, some, findIndex, forEach, join or reduce now returns a native vector of the checked values. The program never observes the array itself, so the checked-dynamic array and, for for-of, the dynamic iterator protocol are skipped. Typed records fill the vector through their record ops table and plain data objects from their entries in own-key order. Other uses, and JavaScript files, keep the checked-dynamic array.
66 lines
1.8 KiB
TypeScript
66 lines
1.8 KiB
TypeScript
// Loop control over Object.values of unknown values: break, continue,
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// return, labeled loops, exceptions from the body, and nested loops.
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interface Row { a: number; b: string; c: number[]; d?: boolean }
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const rows: Row[] = [
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{ a: 1, b: "one", c: [1] },
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{ a: 2, b: "two", c: [2, 2], d: true },
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{ a: 3, b: "three", c: [] },
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];
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function firstString(u: any): string | null {
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for (const v of Object.values(u)) if (typeof v === "string") return v;
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return null;
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}
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function numbersOnly(u: any): number {
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let total = 0;
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for (const v of Object.values(u)) {
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if (typeof v !== "number") continue;
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total += v;
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}
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return total;
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}
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function untilArray(u: any): string[] {
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const out: string[] = [];
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for (const v of Object.values(u)) {
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if (Array.isArray(v)) break;
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out.push(String(v));
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}
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return out;
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}
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for (const row of rows) console.log(firstString(row), numbersOnly(row), untilArray(row).join("/"));
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const pairs: string[] = [];
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const second: any = rows[1];
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const first: any = rows[0];
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outer: for (const x of Object.values(second)) {
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for (const y of Object.values(first)) {
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if (y === "one") continue outer;
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if (x === true) break outer;
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pairs.push(`${String(x)}:${String(y)}`);
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}
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}
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console.log(pairs.join(" "));
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function throwing(u: any): string {
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const seen: string[] = [];
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try {
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for (const v of Object.values(u)) {
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seen.push(String(v));
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if (typeof v === "string") throw new Error(`stop at ${v}`);
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}
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} catch (e) {
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seen.push((e as Error).message);
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} finally {
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seen.push("finally");
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}
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return seen.join(",");
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}
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console.log(throwing(rows[2]));
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let calls = 0;
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const counted: any = { get x() { calls++; return calls; }, y: 0 };
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for (const v of Object.values(counted)) if (v === 1) break;
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for (const v of Object.values(counted)) void v;
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console.log(calls);
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