tsz-emit - SKILL.md Agent Skill

name: tsz-emit description: Write better tsz JavaScript and declaration emit code. Use when changing crates/tsz-emitter, emit transforms, DTS output, source maps, helper scheduling, temp/hoist planning, target/module output, or emit parity tests.

TSZ Emit

Use for JS/DTS emit, transforms, helpers, temp/hoist planning, target/module output, source maps, and emit parity tests.

Start

Read AGENTS.md and docs/plan/ROADMAP.md for durable emit/DTS work.
Inspect overlapping emit PRs/issues.
Name the failure family: target gate, module/export schedule, helper, temp/ hoist, region transform, printer layout, DTS nameability/portability, source maps, or parser recovery.
State: When <syntax/output context>, tsc emits X; tsz emits X through <owner>.

Architecture

Emit is OUTPUT: no checker/solver semantic validation in emitter code.
Prefer planned facts before writing text: target/module facts, helper needs, temp reservations, hoists, prologues, exports, resource/disposable regions.
Keep direct-to-target emit; do not introduce an ESNext -> ... -> ES5 pipeline.
No semantic output surgery with replace, replacen, or replace_range. Data cleanup is fine for escaping, source-map paths, numeric separators, and path normalization.
DTS should use declaration summaries/structured emission, not late string rewrites.

Hot Checks

Use writer/list/token/source-map helpers; add delimiter helpers when they prevent real mistakes.
Target/module policy belongs in target/module facts or emit-plan-like owners, not random printer branches.
Every function-like body needs temp scope and hoist strategy. Bypasses of emit_block must still handle function-body flags and insertion points.
Check adjacent shapes: arrows, declarations, expressions, methods, accessors, constructors, async/generator wrappers, static blocks, namespaces/modules, parameter prologues, ES2015+ and relevant legacy targets.

Verification

No full emit/conformance/fourslash locally.

scripts/emit/run.sh --filter=<family> --js-only --verbose --json-out=/tmp/<name>.json
scripts/emit/run.sh --filter=<family> --dts-only --verbose --json-out=/tmp/<name>.json
cargo nextest run -p tsz-emitter <test-or-family>

PR body: Goal: hold, failure family, structural rule, owner layer, why no semantic validation/output surgery, targeted verification, unsupported shapes.