Apply prefer-const lint rule

lib/db.js

@@ -144,7 +144,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
   const projectionTree = {};
   function func(path, pats, projTree) {
     const children = {};
-    for (let pat of pats) {
+    for (const pat of pats) {
       const fragment = pat[0][path.length] || "*";
       if (fragment === "*") {
         if (pat[1] << path.length) projection[path.join(".")] = 1;
@@ -172,7 +172,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
       }
     }
 
-    for (let [k, v] of Object.entries(children))
+    for (const [k, v] of Object.entries(children))
       func(path.concat(k), v, projTree[k]);
   }
 
@@ -187,7 +187,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
 
   projection = optimizeProjection(projection);
 
-  for (let k of Object.keys(projection)) {
+  for (const k of Object.keys(projection)) {
     if (k === "" || k === "Events" || k.startsWith("Events.")) {
       if (k === "" || k === "Events" || k === "Events._writable") {
         res.push([
@@ -343,7 +343,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
         res.push([path, t, attrs]);
       }
 
-      for (let [k, v] of Object.entries(obj)) {
+      for (const [k, v] of Object.entries(obj)) {
         if (!k.startsWith("_")) {
           obj["_object"] = true;
           storeParams(
@@ -358,7 +358,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
       }
 
       if (!descendantsFetched) {
-        for (let k of Object.keys(projTree)) {
+        for (const k of Object.keys(projTree)) {
           const p = path.concat(k);
           loaded.push([p, ((1 << path.length) - 1) ^ ((1 << MAX_DEPTH) - 1)]);
           if ((obj["_object"] || !path.length) && obj["_timestamp"])
@@ -369,7 +369,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
       }
     }
 
-    for (let [k, v] of Object.entries(device)) {
+    for (const [k, v] of Object.entries(device)) {
       switch (k) {
         case "_lastInform":
           res.push([
@@ -519,7 +519,7 @@ function fetchDevice(id, timestamp, patterns, callback) {
 function saveDevice(deviceId, deviceData, isNew, sessionTimestamp, callback) {
   const update = { $set: {}, $unset: {}, $addToSet: {}, $pull: {} };
 
-  for (let diff of deviceData.timestamps.diff()) {
+  for (const diff of deviceData.timestamps.diff()) {
     if (diff[0].wildcard !== 1 << (diff[0].length - 1)) continue;
 
     if (
@@ -552,7 +552,7 @@ function saveDevice(deviceId, deviceData, isNew, sessionTimestamp, callback) {
     }
   }
 
-  for (let diff of deviceData.attributes.diff()) {
+  for (const diff of deviceData.attributes.diff()) {
     if (diff[1] === diff[2]) continue;
 
     const path = diff[0];
@@ -647,7 +647,7 @@ function saveDevice(deviceId, deviceData, isNew, sessionTimestamp, callback) {
           continue;
         }
 
-        for (let attrName of Object.keys(diff[2])) {
+        for (const attrName of Object.keys(diff[2])) {
           // Param timestamps may be greater than session timestamp to track revisions
           if (diff[2][attrName][0] > sessionTimestamp)
             diff[2][attrName][0] = sessionTimestamp;
@@ -694,7 +694,7 @@ function saveDevice(deviceId, deviceData, isNew, sessionTimestamp, callback) {
         }
 
         if (diff[1]) {
-          for (let attrName of Object.keys(diff[1])) {
+          for (const attrName of Object.keys(diff[1])) {
             if (
               diff[1][attrName][1] != null &&
               (!diff[2] || !diff[2][attrName] || !diff[2][attrName][1])
@@ -716,16 +716,16 @@ function saveDevice(deviceId, deviceData, isNew, sessionTimestamp, callback) {
   // to regular parameters or vice versa. Reason being that _timestamp
   // represents two different things depending on whether the parameter
   // is an object or not.
-  for (let k of Object.keys(update["$unset"]))
+  for (const k of Object.keys(update["$unset"]))
     if (update["$set"][k] != null) delete update["$unset"][k];
 
   // Remove empty keys
-  for (let [k, v] of Object.entries(update)) {
+  for (const [k, v] of Object.entries(update)) {
     if (k === "$addToSet") {
-      for (let [kk, vv] of Object.entries(v))
+      for (const [kk, vv] of Object.entries(v))
         if (!vv["$each"].length) delete v[kk];
     } else if (k === "$pull") {
-      for (let [kk, vv] of Object.entries(v))
+      for (const [kk, vv] of Object.entries(v))
         if (!vv["$in"].length) delete v[kk];
     }
     if (!Object.keys(v).length) delete update[k];