chore(config): add biome lint tooling

Author: fbosch

biome.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "https://biomejs.dev/schemas/2.4.7/schema.json",
+  "vcs": {
+    "enabled": true,
+    "clientKind": "git",
+    "useIgnoreFile": true
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space"
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "quoteStyle": "double",
+      "semicolons": "always"
+    }
+  }
+}

bun.lock

@@ -45,6 +45,8 @@
   "scripts": {
     "bench": "bun scripts/benchmark-json-detection.ts",
     "build": "tsc -p tsconfig.json",
+    "format": "biome check --write .",
+    "lint": "biome check .",
     "prepublishOnly": "bun audit && bun run test && bun run build",
     "release": "bun run typecheck && bunx bumpp && bun publish --access public",
     "test": "bun test --passWithNoTests",
@@ -54,6 +56,7 @@
     "@toon-format/toon": "^2.1.0"
   },
   "devDependencies": {
+    "@biomejs/biome": "^2.4.7",
     "@opencode-ai/plugin": "*",
     "@types/node": "^24.5.2",
     "bumpp": "^10.2.3",

package.json

@@ -168,7 +168,7 @@ function makeJsonLookingGarbage(rng: () => number) {
     () => `${randomWord(rng, 3, 8)}:${randomWord(rng, 3, 12)}`,
   ).join(",");
 
-  return `{${inner}`.padEnd(MIN_LENGTH + 40, "!") + "}";
+  return `${`{${inner}`.padEnd(MIN_LENGTH + 40, "!")}}`;
 }
 
 function sampleDataset(kind: "mostly-non-json" | "mixed" | "mostly-json") {
@@ -242,14 +242,20 @@ function formatPercent(value: number) {
 
 function runToonBenchmark(name: string, dataset: string[]) {
   const results = [
-    summarizeToonVariant(TOON_BASELINE_LABEL, (parsed) => encode(parsed), dataset),
+    summarizeToonVariant(
+      TOON_BASELINE_LABEL,
+      (parsed) => encode(parsed),
+      dataset,
+    ),
     summarizeToonVariant(
       TOON_VARIANT_LABEL,
       (parsed) => encode(parsed, TOON_VARIANT_OPTIONS),
       dataset,
     ),
   ];
-  const baseline = results[0]!;
+  const [baseline] = results;
+
+  if (!baseline) return;
 
   console.log(`TOON benchmark: ${name}`);
   for (const result of results) {
@@ -262,7 +268,8 @@ function runToonBenchmark(name: string, dataset: string[]) {
     const timeDelta =
       baseline.durationMs === 0
         ? 0
-        : ((result.durationMs - baseline.durationMs) / baseline.durationMs) * 100;
+        : ((result.durationMs - baseline.durationMs) / baseline.durationMs) *
+          100;
 
     console.log(
       `${result.name}: ${result.durationMs.toFixed(2)}ms, ${result.shorterCount}/${result.encodedCount} shorter, total chars ${result.totalOutputLength}${result === baseline ? "" : ` | size delta: ${formatPercent(sizeDelta)} | time delta: ${formatPercent(timeDelta)}`}`,
@@ -309,7 +316,9 @@ for (const scenario of ["mostly-non-json", "mixed", "mostly-json"] as const) {
     benchmark("trim-guarded-parse-charcode", guardedParseCharCode, dataset),
     benchmark("bounds-guarded-parse", boundsGuardedParse, dataset),
   ];
-  const baseline = results[0]!;
+  const [baseline] = results;
+
+  if (!baseline) continue;
 
   console.log(`\nScenario: ${scenario}`);
   for (const result of results) {
@@ -328,7 +337,9 @@ for (const scenario of ["mostly-non-json", "mixed", "mostly-json"] as const) {
       dataset,
     ),
   ];
-  const looksLikeJsonBaseline = looksLikeJsonResults[0]!;
+  const [looksLikeJsonBaseline] = looksLikeJsonResults;
+
+  if (!looksLikeJsonBaseline) continue;
 
   console.log("looksLikeJson only:");
   for (const result of looksLikeJsonResults) {
@@ -344,7 +355,9 @@ for (const scenario of ["mostly-non-json", "mixed", "mostly-json"] as const) {
 
 const toonDatasets = {
   tabular: Array.from({ length: 20 }, () => makeLongJson(createRng(101))),
-  nested: Array.from({ length: 20 }, () => makeNestedWrapperJson(createRng(202))),
+  nested: Array.from({ length: 20 }, () =>
+    makeNestedWrapperJson(createRng(202)),
+  ),
   mixed: Array.from({ length: 10 }, () => makeLongJson(createRng(303))).concat(
     Array.from({ length: 10 }, () => makeNestedWrapperJson(createRng(404))),
   ),

scripts/benchmark-json-detection.ts

@@ -1,5 +1,5 @@
-import { encode } from "@toon-format/toon";
 import type { Plugin } from "@opencode-ai/plugin";
+import { encode } from "@toon-format/toon";
 
 const DEFAULT_ELIGIBLE_TOOLS = ["bash"];
 const TOON_OPTIONS = {

src/index.ts

@@ -3,7 +3,10 @@ import test from "node:test";
 
 import ToonPlugin from "../src/index";
 
-const LONG_JSON = JSON.stringify({ hello: "world", items: Array.from({ length: 80 }, (_, i) => i) });
+const LONG_JSON = JSON.stringify({
+  hello: "world",
+  items: Array.from({ length: 80 }, (_, i) => i),
+});
 
 function createOutput() {
   return {