fix isFile bug

was previously using `fs.lstatSync().isFile()`. The `isFile()` method doesnt seem to exist so i went with `fs.existsSync()` instead.

lib/node.js

@@ -3,39 +3,39 @@ import fs from "fs"
 
 
 export const Node = {
-    isFile:function(filename){
-        try {
-            return fs.lstatSync(filename).isFile()
-        } catch (err) {
-            console.log(err)
-            return false
-        }
-
-    },
-    getFullPath:function(folderPath){
-        return fs.readdirSync(folderPath).map(fn  => path.join(folderPath, fn))
-    },
-    getFiles: function(dir) {
-        var results = [];
-        var list = fs.readdirSync(dir);
-        list.forEach(function(file) {
-            file = dir + '/' + file;
-            var stat = fs.statSync(file);
-            if (stat && stat.isDirectory()) { 
-                /* Recurse into a subdirectory */
-                results = results.concat(Node.getFiles(file));
-            } else { 
-                /* Is a file */
-                results.push(file);
-            }
-        });
-        return results.filter(f => f.endsWith(".md"))
-    },
-    readFileSync:function(fullPath){
-        return fs.readFileSync(fullPath, "utf8")
-    },
-
-    getMarkdownFolder: function () {
-        return path.join(process.cwd(), 'posts')
+  isFile: function(filename) {
+    try {
+      return fs.existsSync(filename)
+    } catch (err) {
+      console.error(err)
+      return false
     }
+
+  },
+  getFullPath: function(folderPath) {
+    return fs.readdirSync(folderPath).map(fn => path.join(folderPath, fn))
+  },
+  getFiles: function(dir) {
+    var results = [];
+    var list = fs.readdirSync(dir);
+    list.forEach(function(file) {
+      file = dir + '/' + file;
+      var stat = fs.statSync(file);
+      if (stat && stat.isDirectory()) {
+        /* Recurse into a subdirectory */
+        results = results.concat(Node.getFiles(file));
+      } else {
+        /* Is a file */
+        results.push(file);
+      }
+    });
+    return results.filter(f => f.endsWith(".md"))
+  },
+  readFileSync: function(fullPath) {
+    return fs.readFileSync(fullPath, "utf8")
+  },
+
+  getMarkdownFolder: function() {
+    return path.join(process.cwd(), 'posts')
+  }
 }