mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-11-02 07:43:42 +08:00
Chris Tate
f521dc91b1
A top-level return in a CommonJS module compiles when declarations follow it. When the return is taken, only code that already exists can observe the bindings it skips: functions and classes created before the return, and function declarations after it. A module where one of them reads a binding declared after the return, or that assigns exports after it, still stops with SC1090. assert.strictEqual and assert.notStrictEqual compare a nullable number, string or boolean (`number | null`, `string | null`) with a scalar, null or undefined through the checked-dynamic SameValue compare, which reports Node's failure messages. notStrictEqual of another nullable value, such as `child.stdin`, against null or undefined tests the value's tag. An initializer-less JavaScript `let` whose writes all agree also takes their type when the writes are calls declared in the standard library, such as `spawn(...)`, and at file scope. A runtime handle that a closure captures takes the handle or undefined. Inside a nested function, a member read on it (`c.address()`, `child.stdin`) reads the handle and throws Node's TypeError while the binding is still undefined; other reads there take the checked-dynamic value.
73 lines
2.7 KiB
TypeScript
73 lines
2.7 KiB
TypeScript
// assert.strictEqual and assert.notStrictEqual compare a nullable number,
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// string or boolean with SameValue against a value of another type or
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// null/undefined, and notStrictEqual compares a nullable stream against
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// null or undefined. Failures report Node's messages.
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import assert from "node:assert";
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import { spawn, spawnSync } from "node:child_process";
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function find(values: number[], value: number): number | null {
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const index = values.indexOf(value);
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return index < 0 ? null : index;
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}
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function label(n: number): string | null {
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return n > 0 ? "positive" : null;
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}
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function ratio(n: number): number | undefined {
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return n === 0 ? undefined : n / n;
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}
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function flag(n: number): boolean | null {
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return n === 0 ? null : n > 0;
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}
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assert.strictEqual(find([1, 2, 3], 2), 1);
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assert.strictEqual(find([1, 2, 3], 9), null);
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assert.notStrictEqual(find([1, 2, 3], 3), null);
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assert.notStrictEqual(find([1, 2, 3], 3), 1);
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assert.strictEqual(label(1), "positive");
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assert.strictEqual(label(-1), null);
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assert.notStrictEqual(label(-1), undefined);
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assert.strictEqual(ratio(0), undefined);
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assert.strictEqual(ratio(-0), undefined);
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assert.strictEqual(flag(2), true);
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assert.strictEqual(flag(0), null);
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assert.strictEqual(null, find([], 1));
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console.log("passing comparisons ok");
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const nan: number | null = Number("x");
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assert.strictEqual(nan, NaN);
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function report(run: () => void): void {
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try {
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run();
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console.log("no throw");
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} catch (e) {
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const error = e as assert.AssertionError;
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console.log(error.name, error.code, error.operator, error.generatedMessage);
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console.log(JSON.stringify(error.message));
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console.log(String(error.actual), String(error.expected));
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}
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}
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report(() => assert.strictEqual(find([1], 1), null));
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report(() => assert.strictEqual(find([1], 2), 0));
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report(() => assert.strictEqual(label(1), null));
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report(() => assert.strictEqual(label(-1), "positive", "label mismatch"));
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report(() => assert.notStrictEqual(find([1], 2), null));
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report(() => assert.notStrictEqual(label(3), "positive"));
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report(() => assert.strictEqual(flag(0), false));
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report(() => assert.strictEqual(find([0], 0), -0));
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const result = spawnSync("true");
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assert.strictEqual(result.status, 0);
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assert.strictEqual(result.signal, null);
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const child = spawn("true", [], { stdio: ["ignore", "pipe", "pipe"] });
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assert.notStrictEqual(child.stdout, null);
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assert.notStrictEqual(child.stdout, undefined);
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assert.notStrictEqual(child.stdin, undefined);
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report(() => assert.notStrictEqual(child.stdin, null));
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assert.strictEqual(child.signalCode, null);
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child.on("close", (code) => {
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assert.strictEqual(child.exitCode, 0);
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assert.strictEqual(child.signalCode, null);
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console.log("child closed", code);
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});
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