Merge pull request 'Hold the shipped source to ECMAScript alone, and run the suite on Deno and Bun' (#39) from runs-anywhere into main

AGENTS.md

@@ -60,6 +60,15 @@ they never reach a consumer.
 
 ## 6. The package contract
 
+- Runs on any ES2022 engine, not only Node — a browser as readily as a server. The shipped source
+  is ECMAScript and nothing else: no host import, no host global, no DOM. `tsconfig.build.json` is
+  that gate, typechecking the shipped files alone, so `node:fs`, `process` and an ES2024 method are
+  compile errors here rather than a consumer's crash there. The standard is the line, never an
+  engine list: one implementing it in part — Hermes is the live doubt, on §10's property escapes
+  and on lookbehind — is out of scope rather than a bug. Node's test runner, the corpus reads and
+  the build are the repo's own,
+  never the library's, and `engines.node` states the floor the shipped JavaScript needs — `>=18` —
+  never the higher one those repo-only tools want.
 - ESM only — no CommonJS build, no dual-package hazard.
 - One entrypoint: built JavaScript, `.d.ts` beside it. Do not add a TypeScript-source entrypoint —
   Node refuses to type-strip under `node_modules` (`ERR_UNSUPPORTED_NODE_MODULES_TYPE_STRIPPING`),
@@ -104,8 +113,9 @@ descends, so a document reports its first error in document order.
   differs from npm → publish and tag `vX.Y.Z`. No bump, no deploy; the bump is each shipping PR's
   deliberate semver judgment.
 - Renovate watches devDependencies, Docker pins and action tags; automerges everything on green CI.
-- Docker images pin the full patch version (`node:24.19.0-alpine3.24`, never `node:24`); actions
-  pin semver tags.
+- Docker images pin the full patch version (`node:24.19.0-alpine3.24`, never `node:24`), as
+  specific as the publisher tags: `oven/bun:1.4.0-alpine` pins Bun's patch and leaves the base
+  floating because Bun publishes nothing narrower. Actions pin semver tags.
 
 ## 10. Tests first, in Docker
 
@@ -113,6 +123,14 @@ Test for the behaviour wanted first, then implement until green. `node --test`,
 Node, tsc and npm never run on the host — only via the pinned images (§9). Tests are independent,
 coverage does not decline, containers are torn down after a run.
 
+The gate runs that same suite under Deno and Bun as well as Node, the three images pinned alike,
+and neither extra leg is Node's proof twice. Deno refuses an extensionless or directory specifier,
+so it holds the module graph to the fully-spelled form a browser can load; Bun runs
+JavaScriptCore, the one engine of the three that is not V8, where the Unicode property escapes
+emphasis matching leans on can disagree. Both refuse a run matching no test, so Node's is the only
+vacuous-green guard, and a test may reach only for what all three `node:` shims carry — the price
+of proving those engines over the corpus rather than over a smoke import.
+
 The floors live in the `test` script, so `npm test` and the gate are one path: 100% of lines and
 functions, and a branch floor that only ever moves upward. It sits below 100 because the guards
 `noUncheckedIndexedAccess` and ADF's optional keys force — `?? []`, `?? {}`, `?.`, an index

README.md

@@ -64,4 +64,5 @@ Personas, never named consumers (AGENTS.md §7):
 ## The package
 
 ESM only, no runtime dependencies, public npmjs. Built JavaScript with `.d.ts` beside it.
-Contract: `AGENTS.md` §5–6.
+Pure ECMAScript at an ES2022 baseline, reaching for no host API; the test suite runs under Node,
+Deno and Bun. Contract: `AGENTS.md` §5–6.

ci.sh

@@ -2,13 +2,19 @@
 set -euo pipefail
 cd "$(dirname "$0")"
 
-image=node:24.19.0-alpine3.24
-in_node() { docker run --rm -u "$(id -u):$(id -g)" -e HOME=/tmp -v "$PWD:/app" -w /app "$image" "$@"; }
+bun_image=oven/bun:1.4.0-alpine
+deno_image=denoland/deno:2.9.6
+node_image=node:24.19.0-alpine3.24
+in_image() {
+  local image=$1 entrypoint=$2
+  shift 2
+  docker run --rm -u "$(id -u):$(id -g)" -e HOME=/tmp -v "$PWD:/app" -w /app --entrypoint "$entrypoint" "$image" "$@"
+}
 
-in_node npm ci
-in_node npm run typecheck
+in_image "$node_image" npm ci
+in_image "$node_image" npm run typecheck
 
-if ! test_output=$(in_node npm test 2>&1); then
+if ! test_output=$(in_image "$node_image" npm test 2>&1); then
   printf '%s\n' "$test_output"
   exit 1
 fi
@@ -17,3 +23,6 @@ if printf '%s' "$test_output" | grep -q 'ℹ tests 0'; then
   echo 'the gate ran zero tests — failing instead of a vacuous green'
   exit 1
 fi
+
+in_image "$deno_image" deno test --allow-read --no-check src/
+in_image "$bun_image" bun test src/

package.json

@@ -10,11 +10,11 @@
   },
   "type": "module",
   "engines": {
-    "node": ">=24"
+    "node": ">=18"
   },
   "scripts": {
     "test": "node --test --experimental-test-coverage --test-coverage-exclude=\"src/**/*.test.ts\" --test-coverage-branches=97 --test-coverage-functions=100 --test-coverage-lines=100 \"src/**/*.test.ts\"",
-    "typecheck": "tsc --noEmit"
+    "typecheck": "tsc --noEmit && tsc --noEmit -p tsconfig.build.json"
   },
   "devDependencies": {
     "@types/node": "24.13.3",

renovate.json

@@ -2,6 +2,15 @@
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "automerge": true,
   "customManagers": [
+    {
+      "customType": "regex",
+      "datasourceTemplate": "docker",
+      "depNameTemplate": "denoland/deno",
+      "description": "Pin the Deno image ci.sh runs",
+      "managerFilePatterns": ["ci.sh"],
+      "matchStrings": ["denoland/deno:(?<currentValue>[0-9][^\\s\"']*)"],
+      "versioningTemplate": "docker"
+    },
     {
       "customType": "regex",
       "datasourceTemplate": "docker",
@@ -11,6 +20,15 @@
       "matchStrings": ["node:(?<currentValue>[0-9][^\\s\"']*)"],
       "versioningTemplate": "docker"
     },
+    {
+      "customType": "regex",
+      "datasourceTemplate": "docker",
+      "depNameTemplate": "oven/bun",
+      "description": "Pin the Bun image ci.sh runs",
+      "managerFilePatterns": ["ci.sh"],
+      "matchStrings": ["oven/bun:(?<currentValue>[0-9][^\\s\"']*)"],
+      "versioningTemplate": "docker"
+    },
     {
       "customType": "regex",
       "datasourceTemplate": "docker",

todo.md

@@ -139,10 +139,17 @@ numbering is the order the work was planned in, not the order it ships.
       additions are read here as one list before that freeze — nine sessions mint them
       independently, and one cause wearing two codes is breaking to undo after `0.1.0`. `0.1.0`
       is the markdown round-trip: both markdown directions, the types, `isAdfDocument`. The build
-      lands here: a build tsconfig emitting JS and `.d.ts` to `dist/` (the dev config's
-      `allowImportingTsExtensions` forces `noEmit`, so the build config needs
-      `rewriteRelativeImportExtensions`), plus `exports`/`files` in `package.json`. The
+      lands here: `tsconfig.build.json` gains emit of JS and `.d.ts` to `dist/` (its own
+      `allowImportingTsExtensions` forces `noEmit`, so `rewriteRelativeImportExtensions` lands
+      beside it), plus `exports`/`files` in `package.json`. The
       maintainer's bump PR also removes `private: true`, the guard against any earlier publish.
+      §6's browser half is first checkable here, on the emitted `dist/index.js` a browser can
+      load — the compile gate names no host API, and a real page converting the corpus is the
+      other half. Headless Firefox is that page, settling both at once: the browser proof, and the
+      only SpiderMonkey there is, `ci.sh`'s three legs being two V8s and a JavaScriptCore that is
+      not Safari's. `engines.node` gets its one-line proof here
+      too — `import('./dist/index.js')` under a pinned Node 18 image, which cannot run the
+      suite that type stripping wants 22+ for, but proves exactly what the field claims.
       **Settled** (the maintainer, 2026-09-01): the round-trip proved over the checked-in corpus
       is what `0.1.0` ships on, and the open-ended proof work follows it rather than gating it —
       3k's spec suite and 4's generators and maintainer-supplied payloads are `0.2.0`, 4b's retry

tsconfig.build.json

@@ -0,0 +1,29 @@
+{
+  "compilerOptions": {
+    "lib": ["ES2022"],
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "target": "ES2022",
+    "types": [],
+
+    "allowImportingTsExtensions": true,
+    "erasableSyntaxOnly": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "verbatimModuleSyntax": true,
+
+    "strict": true,
+    "exactOptionalPropertyTypes": true,
+    "noFallthroughCasesInSwitch": true,
+    "noImplicitOverride": true,
+    "noImplicitReturns": true,
+    "noUncheckedIndexedAccess": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+
+    "forceConsistentCasingInFileNames": true,
+    "skipLibCheck": true
+  },
+  "exclude": ["src/**/*.test.ts"],
+  "include": ["src"]
+}

tsconfig.json

@@ -1,28 +1,9 @@
 {
+  "extends": "./tsconfig.build.json",
   "compilerOptions": {
     "lib": ["ESNext"],
-    "module": "NodeNext",
-    "moduleResolution": "NodeNext",
     "target": "ESNext",
-    "types": ["node"],
-
-    "allowImportingTsExtensions": true,
-    "erasableSyntaxOnly": true,
-    "isolatedModules": true,
-    "noEmit": true,
-    "verbatimModuleSyntax": true,
-
-    "strict": true,
-    "exactOptionalPropertyTypes": true,
-    "noFallthroughCasesInSwitch": true,
-    "noImplicitOverride": true,
-    "noImplicitReturns": true,
-    "noUncheckedIndexedAccess": true,
-    "noUnusedLocals": true,
-    "noUnusedParameters": true,
-
-    "forceConsistentCasingInFileNames": true,
-    "skipLibCheck": true
+    "types": ["node"]
   },
-  "include": ["src"]
+  "exclude": []
 }