Use Number.isNaN() instead of val == NaN

Comparison to NaN is useless. Nothing is equal to NaN, not even NaN. Use Number.isNaN().

Author: hodovani

dist/core/generic.js

@@ -238,9 +238,7 @@ class NDframe {
 
     if (this.series) {
       this.values.map(val => {
-        if (val == NaN) {
-          new_arr.push(true);
-        } else if (isNaN(val) && typeof val != "string") {
+        if (isNaN(val) && typeof val != "string") {
           new_arr.push(true);
         } else {
           new_arr.push(false);
@@ -251,9 +249,7 @@ class NDframe {
       row_data.map(arr => {
         let temp_arr = [];
         arr.map(val => {
-          if (val == NaN) {
-            temp_arr.push(true);
-          } else if (isNaN(val) && typeof val != "string") {
+          if (isNaN(val) && typeof val != "string") {
             temp_arr.push(true);
           } else {
             temp_arr.push(false);
@@ -396,4 +392,4 @@ class NDframe {
 
 }
 
-exports.default = NDframe;
+exports.default = NDframe;