Apply prefer-const lint rule

lib/instance-set.js

@@ -32,10 +32,10 @@ class InstanceSet {
   }
 
   superset(instance) {
-    let res = [];
-    for (let inst of this.set) {
+    const res = [];
+    for (const inst of this.set) {
       let match = true;
-      for (let k in instance) {
+      for (const k in instance) {
         if (inst[k] !== instance[k]) {
           match = false;
           break;
@@ -46,8 +46,8 @@ class InstanceSet {
     }
 
     res.sort((a, b) => {
-      let keysA = Object.keys(a);
-      let keysB = Object.keys(b);
+      const keysA = Object.keys(a);
+      const keysB = Object.keys(b);
 
       if (keysA.length != keysB.length) return keysB.length - keysA.length;
 
@@ -68,11 +68,11 @@ class InstanceSet {
   }
 
   subset(instance) {
-    let res = [];
+    const res = [];
 
-    for (let inst of this.set) {
+    for (const inst of this.set) {
       let match = true;
-      for (let k in inst) {
+      for (const k in inst) {
         if (inst[k] !== instance[k]) {
           match = false;
           break;
@@ -83,8 +83,8 @@ class InstanceSet {
     }
 
     res.sort((a, b) => {
-      let keysA = Object.keys(a);
-      let keysB = Object.keys(b);
+      const keysA = Object.keys(a);
+      const keysB = Object.keys(b);
 
       if (keysA.length != keysB.length) return keysA.length - keysB.length;