deepDiff.ts

export function deepDiff<TObj extends object>(a: TObj, b: TObj) {
  if (Array.isArray(a)) {
    const changes = a
      .map((item, index) => deepDiff(item, b[index]))
      .filter(Boolean)
    return changes.length ? changes : undefined
  }

  if (isObject(a)) {
    const changes = {}
    Object.keys(a).forEach(key => {
      const diff = deepDiff(a[key], b[key])
      if (diff) {
        changes[key] = diff
      }
    })
    return Object.keys(changes).length ? changes : undefined
  }

  return a !== b ? ([a, b] as const) : undefined
}