Apply prefer-const lint rule

lib/common.js

@@ -36,7 +36,7 @@ function generateDeviceId(deviceIdStruct) {
     return str.replace(/[^A-Za-z0-9_]/g, chr => {
       const buf = Buffer.from(chr, "utf8");
       let rep = "";
-      for (let b of buf) rep += "%" + b.toString(16).toUpperCase();
+      for (const b of buf) rep += "%" + b.toString(16).toUpperCase();
       return rep;
     });
   }
@@ -139,7 +139,7 @@ function parsePath(pattern, start, res) {
         path.alias |= 1 << path.length;
         i = parseAlias(pattern, i + 1, path) + 1;
       } else {
-        let j = i;
+        const j = i;
         while (i < pattern.length && pattern[i] !== ":" && pattern[i] !== ".")
           ++i;
 
@@ -169,7 +169,7 @@ function addPathMeta(path) {
   path.alias = 0;
   path.wildcard = 0;
 
-  for (let [i, p] of path.entries()) {
+  for (const [i, p] of path.entries()) {
     if (Array.isArray(p)) {
       path.alias |= 1 << i;
       for (let j = 0; j < p.length; j += 2) addPathMeta(p[j]);