alexion
ae542893da
Split the view command out of the entry point and make its failure a value rather than an exception. index.ts is now scaffolding plus dispatch; view.ts owns the behaviour, returning Result<string, ViewError> (a plain-data tagged union) via neverthrow, with try/catch confined to a readFile adapter. The entry point matches the Result at the boundary. Because viewFile is a pure in-process function it is now unit-tested directly (and counted by coverage), while the subprocess tests stay as the end-to-end check. ADR 0008 records the errors-as-values convention.
28 lines
920 B
TypeScript
28 lines
920 B
TypeScript
import { readFileSync } from "node:fs";
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import { parse } from "@kitchen-md/core";
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import { err, ok, type Result } from "neverthrow";
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import { render } from "./render.ts";
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export type ViewError = { tag: "read-failed"; path: string; cause: string };
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export function viewFile(path: string): Result<string, ViewError> {
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return readFile(path).map((content) => render(parse(content)));
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}
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export function formatViewError(error: ViewError): string {
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switch (error.tag) {
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case "read-failed":
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return `cannot read '${error.path}': ${error.cause}`;
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}
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}
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// The one place a throwing API is turned into a Result; nothing above this leaks exceptions.
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function readFile(path: string): Result<string, ViewError> {
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try {
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return ok(readFileSync(path, "utf8"));
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} catch (error) {
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const cause = error instanceof Error ? error.message : String(error);
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return err({ tag: "read-failed", path, cause });
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}
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}
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