Storyden

/** * Deep equality comparison utility * Based on fast-deep-equal with structural comparison */ export function deepEqual(a: unknown, b: unknown): boolean { if (a === b) return true; if (a && b && typeof a === "object" && typeof b === "object") { if (Array.isArray(a) !== Array.isArray(b)) return false; if (Array.isArray(a)) { const length = a.length; if (length !== (b as unknown[]).length) return false; for (let i = length; i-- !== 0; ) { if (!deepEqual(a[i], (b as unknown[])[i])) return false; } return true; } if (a instanceof Date && b instanceof Date) { return a.getTime() === b.getTime(); } if (a instanceof RegExp && b instanceof RegExp) { return a.toString() === b.toString(); } const keys = Object.keys(a); const length = keys.length; if (length !== Object.keys(b).length) return false; for (let i = length; i-- !== 0; ) { const key = keys[i]; if (key === undefined || !Object.prototype.hasOwnProperty.call(b, key)) return false; } for (let i = length; i-- !== 0; ) { const key = keys[i]; if (key === undefined) return false; if ( !deepEqual( (a as Record<string, unknown>)[key], (b as Record<string, unknown>)[key], ) ) { return false; } } return true; } return a !== a && b !== b; // NaN case }