vercel-labs/scriptc v0.2.8

on GitHub

0.2.8

Features

• Workers can share immutable object graphs without copying. The new @scriptc/threads package adds publish(value), which makes a graph read-only so native executables hand the same objects to every worker by reference; Node.js runs its JavaScript implementation. Deeply frozen plain data sent to workers is also shared rather than cloned.
• Deep recursion throws a catchable RangeError. Recursive functions check the native stack on Linux and macOS and throw RangeError: Maximum call stack size exceeded on the main thread, in workers, and inside async functions and generators, which now run on 512 KiB stacks.
• Compile blockers and Node.js differences are easier to act on. Diagnostics explain what stopped a compile and where native behavior differs, and a rejected declaration now reports its own diagnostic instead of only a follow-on error.

Performance

• Large executables compile faster and rebuild incrementally. Code is divided into partitions that are optimized and compiled in parallel, with small functions imported across partitions for inlining, and rebuilds reuse the partitions an edit does not touch.
• Native code does less reference-count and allocation work. Nullable references are stored as plain pointers, release fast paths are inlined without cycle-color writes, more parameters, receivers and locals are borrowed, provably 32-bit integer fields and values use native integers, and temporary arrays are avoided.
• Strings, collections, loops and exceptions use more direct paths. Strings cache a proven-ASCII flag and read elements inline, number-keyed Maps and Sets index directly, loops over arrays without holes read elements directly, and exception checks run inline.
• Programs that create workers pay far less overhead. A per-thread allocator, initial-exec thread-local storage and a single exception alert word keep single-threaded code in worker programs close to its non-worker speed.

Fixes

• More values behave as in Node.js. Out-of-range typed array reads, holes in for...of loops, object literals built from missing array elements, and class fields read before assignment all produce undefined. Optional values keep their state through callbacks, captures, pop() and initialization order.
• Weak collections accept more keys. Records and arrays reached through unions and empty object literals work as WeakMap and WeakSet keys.
• Debuggers stop only at user code. Shared helpers no longer appear on user source lines, so a breakpoint on a line stops only at that line's code.
• Native program objects use runtime ABI v9. External object consumers must link the matching v0.2.8 runtime pack; the versioned marker rejects incompatible runtime objects at link time.