null,NaN,undefiend will be treated as undedined

README.md

@@ -84,6 +84,8 @@ Solve the problem of **big number** precision loss, using string representation.
 
 If the value of plain object is **null** / **undefiend** / **NaN**, it will be discarded.
 
+**null**,**undefiend**,**NaN** will be treated as **undefined**. 
+
 **Regular expression** parsing is supported.
 
 **Bigint** parsing is supported, using string representation.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "json-enhancer",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "description": "Extension JavaScript native parser for ES new features.",
   "main": "lib/json-enhancer.cjs",
   "unpkg": "dist/json-enhancer.js",

src/index.js

@@ -5,6 +5,7 @@ const Types = [
   'regexp',
   'set',
   'symbol',
+  'undefined',
 ].reduce((acc, cur) => {
   acc[cur] = `[@@EnhancerJSON/${cur.toUpperCase()}]`;
   return acc;
@@ -63,6 +64,8 @@ export function decodeJSON(param) {
   const result = JSON.parse(
     _innerParam,
     function (key, value) {
+      if (value === null) return undefined;
+
       if (typeof value !== 'string') return value;
 
       if (value.startsWith(Types.function)) {
@@ -89,6 +92,10 @@ export function decodeJSON(param) {
         return Symbol(value.slice(Types.symbol.length));
       }
 
+      if (value.startsWith(Types.undefined)) {
+        return undefined;
+      }
+
       return value;
     });
 
@@ -102,7 +109,10 @@ export function encodeJSON(p) {
 
   return JSON.stringify(param, function (key, value) {
     if (typeof value === 'function') return Types['function'] + value.toString();
-
+    if (
+      value === null ||
+      value === undefined ||
+      Number.isNaN(value)) return value = Types['undefined'] + 'undefined';
     if (isISOString(value)) return Types['date'] + Date.parse(value);
 
     if (typeof value === 'bigint') return String(value);

src/index.test.js

@@ -41,6 +41,14 @@ describe('combination:encodeJSON + decodeJSON', () => {
     ).toEqual(targetObj);
   });
 
+  test('null, undefined, NaN are unified undefined', () => {
+    const arr = [null, NaN, undefined, 'null', 1, 'NaN', 'undefined'];
+
+    expect(
+      decodeJSON(encodeJSON(arr))
+    ).toEqual([undefined, undefined, undefined, 'null', 1, 'NaN', 'undefined']);
+  });
+
   test('Regular expression', () => {
     const reg = new RegExp('ab+c', 'i');
     const regCopy = decodeJSON(encodeJSON(reg));