remove use of deprecated 'new Buffer' instanciation

historyKeeper.js

@@ -284,7 +284,7 @@ module.exports.create = function (cfg) {
 
     const storeMessage = function (ctx, channel, msg, isCp, optionalMessageHash) {
         const id = channel.id;
-        const msgBin = new Buffer(msg + '\n', 'utf8');
+        const msgBin = Buffer.from(msg + '\n', 'utf8');
 
         queueStorage(id, function (next) {
             // Store the message first, and update the index only once it's stored.

rpc.js

@@ -1062,7 +1062,7 @@ var writeLoginBlock = function (Env, msg, cb) { // FIXME BLOCKS
             // flow is dumb and I need to guard against this which will never happen
             /*:: if (typeof(validatedBlock) === 'undefined') { throw new Error('should never happen'); } */
             /*:: if (typeof(path) === 'undefined') { throw new Error('should never happen'); } */
-            Fs.writeFile(path, new Buffer(validatedBlock), { encoding: "binary", }, function (err) {
+            Fs.writeFile(path, Buffer.from(validatedBlock), { encoding: "binary", }, function (err) {
                 if (err) { return void cb(err); }
                 cb();
             });

storage/file.js

@@ -832,7 +832,7 @@ const messageBin = (env, chanName, msgBin, cb) => {
 
 // append a string to a channel's log as a new line
 var message = function (env, chanName, msg, cb) {
-    messageBin(env, chanName, new Buffer(msg + '\n', 'utf8'), cb);
+    messageBin(env, chanName, Buffer.from(msg + '\n', 'utf8'), cb);
 };
 
 // stream messages from a channel log

www/common/common-util.js

@@ -3,7 +3,7 @@
 
     // polyfill for atob in case you're using this from node...
     window.atob = window.atob || function (str) { return Buffer.from(str, 'base64').toString('binary'); }; // jshint ignore:line
-    window.btoa = window.btoa || function (str) { return new Buffer(str, 'binary').toString('base64'); }; // jshint ignore:line
+    window.btoa = window.btoa || function (str) { return Buffer.from(str, 'binary').toString('base64'); }; // jshint ignore:line
 
     Util.slice = function (A, start, end) {
         return Array.prototype.slice.call(A, start, end);