Refactor: add parseCacheCompressionOption helper

Extract a small parser for BUILD_CACHE_COMPRESSION to centralize the mapping of
env values to webpack filesystem cache 'compression' option. Improves readability
and keeps the previous behavior (undefined=webpack default, '',0,false,none=false,
else 'gzip'|'brotli' or warn->false). Verified with prettier, ESLint and build.

Author: PeterDaveHello

build.mjs

@@ -17,21 +17,15 @@ const isAnalyzing = process.argv[2] === '--analyze'
 const parallelBuild = process.env.BUILD_PARALLEL !== '0'
 const isWatchOnce = !!process.env.BUILD_WATCH_ONCE
 // Cache compression control: default none; allow override via env
-const cacheCompressionEnv = process.env.BUILD_CACHE_COMPRESSION
-let cacheCompressionOption
-if (cacheCompressionEnv != null) {
-  const v = String(cacheCompressionEnv).trim().toLowerCase()
-  if (v === '' || v === '0' || v === 'false' || v === 'none') {
-    cacheCompressionOption = false
-  } else if (v === 'gzip' || v === 'brotli') {
-    cacheCompressionOption = v
-  } else {
-    console.warn(
-      `[build] Unknown BUILD_CACHE_COMPRESSION="${cacheCompressionEnv}", defaulting to no compression`,
-    )
-    cacheCompressionOption = false
-  }
+function parseCacheCompressionOption(envVal) {
+  if (envVal == null) return undefined
+  const v = String(envVal).trim().toLowerCase()
+  if (v === '' || v === '0' || v === 'false' || v === 'none') return false
+  if (v === 'gzip' || v === 'brotli') return v
+  console.warn(`[build] Unknown BUILD_CACHE_COMPRESSION="${envVal}", defaulting to no compression`)
+  return false
 }
+const cacheCompressionOption = parseCacheCompressionOption(process.env.BUILD_CACHE_COMPRESSION)
 let cpuCount = 1
 try {
   const cpuInfo = os.cpus && os.cpus()
@@ -40,26 +34,25 @@ try {
 } catch {
   cpuCount = 1
 }
-const rawWorkers = process.env.BUILD_THREAD_WORKERS
-  ? parseInt(process.env.BUILD_THREAD_WORKERS, 10)
-  : undefined
-let threadWorkers
-if (Number.isInteger(rawWorkers) && rawWorkers > 0) {
+function parseThreadWorkerCount(envValue, cpuCount) {
   const maxWorkers = Math.max(1, cpuCount)
-  if (rawWorkers > maxWorkers) {
-    console.warn(
-      `[build] BUILD_THREAD_WORKERS=${rawWorkers} exceeds CPU count (${cpuCount}); capping to ${maxWorkers}`,
-    )
-  }
-  threadWorkers = Math.min(rawWorkers, maxWorkers)
-} else {
-  if (process.env.BUILD_THREAD_WORKERS) {
+  if (envValue !== undefined && envValue !== null) {
+    const raw = parseInt(envValue, 10)
+    if (Number.isInteger(raw) && raw > 0) {
+      if (raw > maxWorkers) {
+        console.warn(
+          `[build] BUILD_THREAD_WORKERS=${raw} exceeds CPU count (${cpuCount}); capping to ${maxWorkers}`,
+        )
+      }
+      return Math.min(raw, maxWorkers)
+    }
     console.warn(
-      `[build] Invalid BUILD_THREAD_WORKERS="${process.env.BUILD_THREAD_WORKERS}", defaulting to CPU count (${cpuCount})`,
+      `[build] Invalid BUILD_THREAD_WORKERS="${envValue}", defaulting to CPU count (${cpuCount})`,
     )
   }
-  threadWorkers = cpuCount
+  return maxWorkers
 }
+const threadWorkers = parseThreadWorkerCount(process.env.BUILD_THREAD_WORKERS, cpuCount)
 // Thread-loader pool timeout constants (allow override via env)
 let PRODUCTION_POOL_TIMEOUT_MS = 2000
 if (process.env.BUILD_POOL_TIMEOUT) {