wcb/size-change-log.md
Ayo 248ef14322 fix: no TypeErorr for default props; add strictProps
- Remove thrown error if type difference is found in defined props
- Introduce strictProps toggle for error behavior
- Extract size changes to its own log file
2026-07-05 11:11:36 +02:00

2.7 KiB

Size change log

A running record of how each correctness/feature change affects the WebComponent base class bundle, measured as min + brotli via size-limit. Baseline before the Phase 0 correctness work: 1.19 kB (limit 1.2 kB).

Change Size (min+brotli) Limit Reason & benefit
Move default-attribute reflection out of the constructor ~1.19 kB (≈0) 1.2 kB Custom Elements Spec compliance. Constructors may not mutate attributes, so document.createElement on a class with static props threw NotSupportedError in real browsers. Defaults now reflect on first connect, and markup/SSR-provided attributes win. Pure code movement — no net size cost.
Safe prop cloning (functions/instances) + define-time validation 1.31 kB (+0.12 kB) 1.2 → 1.35 kB No more DataCloneError. structuredClone of a function/class-instance default crashed construction. Defaults are now cloned per key (plain data deep-copied so instances don't share object/array state; non-cloneable values kept by reference), and a one-time warning names any default whose type can't reflect to an attribute. Limit raised to fit.
Derive prop types from defaults only; log type violations instead of throwing (+ static strictProps opt-in) 1.33 kB (+0.02 kB) 1.35 kB Loud, not fatal. The proxy setter locked a prop's type on first write and threw on mismatch; inside attributeChangedCallback that TypeError vanished into window.onerror and silently skipped rendering. Types are now taken from static props defaults only (undeclared props stay untyped), and a declared-type violation is logged via console.error and skipped so render()/onChanges() still run. Teams wanting hard enforcement can set static strictProps = true to restore throwing.