async function generateTopLevelArrays()

in packages/tasks-gen/scripts/inference-codegen.ts [200:263]
57 lines of code
7 McCabe index (conditional complexity)

async function generateTopLevelArrays(path2generated: string, outputSpec: Record<string, unknown>): Promise<void> {
	const source = ts.createSourceFile(
		path.basename(path2generated),
		await fs.readFile(path2generated, { encoding: "utf-8" }),
		ts.ScriptTarget.ES2022
	);
	const exportedName = outputSpec.title;
	if (outputSpec.type !== "array" || typeof exportedName !== "string") {
		console.log("      Nothing to do");
		return;
	}
	const topLevelNodes = source.getChildAt(0).getChildren();
	const hasTypeAlias = topLevelNodes.some(
		(node) =>
			node.kind === ts.SyntaxKind.TypeAliasDeclaration &&
			(node as ts.TypeAliasDeclaration).name.escapedText === exportedName
	);
	if (hasTypeAlias) {
		return;
	}

	const interfaceDeclaration = topLevelNodes.find((node): node is ts.InterfaceDeclaration => {
		if (node.kind === ts.SyntaxKind.InterfaceDeclaration) {
			return (node as ts.InterfaceDeclaration).name.getText(source) === exportedName;
		}
		return false;
	});
	if (!interfaceDeclaration) {
		console.log("      Nothing to do");
		return;
	}

	console.log("      Inserting top-level array type alias...");

	const updatedInterface = ts.factory.updateInterfaceDeclaration(
		interfaceDeclaration,
		interfaceDeclaration.modifiers,
		ts.factory.createIdentifier(interfaceDeclaration.name.getText(source) + "Element"),
		interfaceDeclaration.typeParameters,
		interfaceDeclaration.heritageClauses,
		interfaceDeclaration.members
	);
	const arrayDeclaration = ts.factory.createTypeAliasDeclaration(
		[ts.factory.createModifier(ts.SyntaxKind.ExportKeyword)],
		exportedName,
		undefined,
		ts.factory.createArrayTypeNode(ts.factory.createTypeReferenceNode(updatedInterface.name))
	);

	const printer = ts.createPrinter();

	const newNodes = ts.factory.createNodeArray([
		...topLevelNodes.filter((node) => node !== interfaceDeclaration),
		arrayDeclaration,
		updatedInterface,
	]);

	await fs.writeFile(path2generated, printer.printList(ts.ListFormat.MultiLine, newNodes, source), {
		flag: "w+",
		encoding: "utf-8",
	});

	return;
}