Task Scheduler

Ownership and transitions

Priority dispatch and lease ownership are separate state machines. Expiry makes a task pending at the exact boundary; reassignment receives a fresh token, so an older completion cannot finish the new lease. Timed failures still expire old leases and advance accepted time. Invalid lease duration must be rejected before time advances. Scan-based dispatch/expiry costs O(tasks) plus priority sorting; heaps need stale-entry handling.

JavaScript boundaries

Use native classes with per-instance state and plain object/array snapshots. Object assignment shares a reference; copy retained inputs and every outward mutable container, including nested arrays. null means absence. Map handles arbitrary string keys safely, including "__proto__"; do not confuse a missing key with zero or an empty string. Domain validation uses RangeError. Numeric inputs must satisfy Number.isSafeInteger, so booleans, fractions, infinities, and NaN are invalid where an integer is required. All documented aggregate results and timestamp-plus-duration sums fit the safe-integer range. Strings use exact case-sensitive equality; lexical order compares JavaScript UTF-16 code units. Calls are serialized and synchronous.

const internal = ["initial"];
const snapshot = [...internal];
snapshot.length = 0;
console.assert(internal.length === 1);

A detached snapshot protects ownership; the service still has to validate and commit a coherent transition.