const MAX_DEPTH = 20;
const MAX_DEPTH_ERROR = `stableStringify: Max depth (${MAX_DEPTH}) exceeded`;
const CIRCULAR_ERROR = 'stableStringify: Circular reference detected';
function compareObjectKeys(a: string, b: string): number {
if (a === b) return 0;
return a < b ? -1 : 1;
}
function getSortedObjectKeys(obj: object): string[] {
return Object.keys(obj).sort(compareObjectKeys);
}
function processValue(
obj: unknown,
depth: number,
seen: WeakSet<object>
): unknown {
if (typeof obj !== 'object' || obj === null) {
return obj;
}
// Depth guard
if (depth > MAX_DEPTH) {
throw new Error(MAX_DEPTH_ERROR);
}
// Cycle detection (track active recursion stack only).
if (seen.has(obj)) {
throw new Error(CIRCULAR_ERROR);
}
seen.add(obj);
try {
if (Array.isArray(obj)) {
return obj.map((item) => processValue(item, depth + 1, seen));
}
const keys = getSortedObjectKeys(obj);
const record = obj as Record<string, unknown>;
const sortedObj: Record<string, unknown> = {};
for (const key of keys) {
sortedObj[key] = processValue(record[key], depth + 1, seen);
}
return sortedObj;
} finally {
seen.delete(obj);
}
}
export function stableStringify(
obj: unknown,
depth = 0,
seen = new WeakSet()
): string {
const processed = processValue(obj, depth, seen);
return JSON.stringify(processed);
}
