feat(@websnacksjs/conventional): initial implementation

`@websnacksjs/conventional` is a cli program which can be used with
`husky` & git hooks to enforce that commit messages adhere to the
conventional commits standard.

packages/conventional/src/lib/utils/error.ts

@@ -0,0 +1,28 @@
+export const normalizeError = (error: unknown): Error => {
+	if (!(error instanceof Error)) {
+		error = new Error(`non-Error type thrown: ${JSON.stringify(error)}`);
+	}
+	return error as Error;
+};
+
+const errorCauseChain = (error: Error): Error[] => {
+	const causeChain: Error[] = [];
+	let cause = error.cause;
+	while (cause !== undefined) {
+		causeChain.push(normalizeError(cause));
+
+		if (cause instanceof Error) {
+			cause = cause.cause;
+		}
+	}
+	return causeChain;
+};
+
+export const formatError = (error: Error): string => {
+	let message = error.message;
+	const causeChain = errorCauseChain(error);
+	for (const cause of causeChain) {
+		message += `: ${cause.message}`;
+	}
+	return message;
+};