Object Update II

Requirements

• Export updateObject(input, operations) as named and default. Each operation is { path: readonly (string | number)[], update: (current: unknown) => unknown }. Apply operations in order; later updaters observe the result of earlier operations. Return the final root. This version takes a batch rather than the first version’s single path/updater.
• Use copy-on-write at every changed path. Preserve references for unaffected branches. If an updater returns an Object.is-equal value, that operation returns its current root unchanged. An empty batch returns the original root; an empty path replaces the whole root.
• Missing own properties and primitive intermediate values are treated as undefined. Create an array for a numeric segment and an ordinary object for a string segment when an intermediate container is missing or primitive. Numeric segments must be integers from 0 through 4294967294. Array paths require numeric indexes, may extend length, and preserve sparse holes. Existing plain objects preserve their prototype.
• Read only own properties. Validate every operation’s shape and path before calling any updater. Reject __proto__, constructor, and prototype string segments with TypeError, and reject invalid numeric indexes. Reject string segments encountered on an existing array with TypeError.
• Inputs consist of primitives, arrays, and plain/null-prototype objects with own enumerable data properties. Updaters must treat received values as immutable; mutation by a callback is outside scope. Do not mutate input, operation arrays, or paths. Frozen inputs must work. Exceptions propagate exactly and no partially changed root is returned. Cycles, accessors, symbol paths, deleting keys, and arbitrary class instances are excluded.

Examples

Input: updateObject({count:1}, [{path:["count"],update:n=>n+1},{path:["count"],update:n=>n*3}])
Output: {count:6}

Input: updateObject({}, [{path:["items",2,"name"],update:()=>"Ada"}])
Output: Creates a sparse items array with {name:"Ada"} at index 2.