Apply prefer-const lint rule

lib/gpn-heuristic.js

@@ -34,11 +34,11 @@ function estimateGpnCount(gpnPatterns, depth = 0) {
   let wildcardDiscovered = false;
   let gpnCount = 0;
 
-  for (let pattern of gpnPatterns) {
+  for (const pattern of gpnPatterns) {
     const path = pattern[0];
     const flags = pattern[1] >> depth;
 
-    let k = path[depth];
+    const k = path[depth];
 
     if (!k) {
       if (flags & 1) gpnCount = 1;
@@ -67,8 +67,8 @@ function estimateGpnCount(gpnPatterns, depth = 0) {
       estimateGpnCount(wildcardChildren, depth + 1) * WILDCARD_MULTIPLIER;
   }
 
-  for (let k of Object.keys(children)) {
-    let c = estimateGpnCount(children[k].concat(wildcardChildren), depth + 1);
+  for (const k of Object.keys(children)) {
+    const c = estimateGpnCount(children[k].concat(wildcardChildren), depth + 1);
     wildcardGpnCount -= c;
     gpnCount += c;
   }