more functional design principles

test/unit/cotParser.spec.js

@@ -1,19 +1,18 @@
 import { describe, it, expect } from 'vitest'
 import { parseTakStreamFrame, parseTraditionalXmlFrame, parseCotPayload } from '../../../server/utils/cotParser.js'
 
+const encodeVarint = (value, bytes = []) => {
+  const byte = value & 0x7F
+  const remaining = value >>> 7
+  if (remaining === 0) {
+    return [...bytes, byte]
+  }
+  return encodeVarint(remaining, [...bytes, byte | 0x80])
+}
+
 function buildTakFrame(payload) {
   const buf = Buffer.from(payload, 'utf8')
-  let n = buf.length
-  const varint = []
-  while (true) {
-    const byte = n & 0x7F
-    n >>>= 7
-    if (n === 0) {
-      varint.push(byte)
-      break
-    }
-    varint.push(byte | 0x80)
-  }
+  const varint = encodeVarint(buf.length)
   return Buffer.concat([Buffer.from([0xBF]), Buffer.from(varint), buf])
 }
 
@@ -42,14 +41,7 @@ describe('cotParser', () => {
 
     it('returns null for payload length exceeding max', () => {
       const hugeLen = 64 * 1024 + 1
-      const varint = []
-      let n = hugeLen
-      while (true) {
-        varint.push(n & 0x7F)
-        n >>>= 7
-        if (n === 0) break
-        varint[varint.length - 1] |= 0x80
-      }
+      const varint = encodeVarint(hugeLen)
       const buf = Buffer.concat([Buffer.from([0xBF]), Buffer.from(varint)])
       expect(parseTakStreamFrame(buf)).toBeNull()
     })