Check any valid JSON value

README.md

@@ -152,6 +152,23 @@ Default type: object, With option type: bigint
 
 ```
 
+**Exception**: if the number being parsed is a big decimal number, still returns it as BigNumber.
+
+```js
+var JSONbig = require('json-bigint');
+var JSONbigNative = require('json-bigint')({ useNativeBigInt: true });
+var key = '{ "key": 993143214321423154315154321.1 }';
+console.log(`\n\nStoring the Number as a BigNumber!!`);
+console.log('Input:', key);
+var normal = JSONbig.parse(key);
+var nativeBigInt = JSONbigNative.parse(key);
+console.log(
+  'Default type: %s, With option type: %s',
+  typeof normal.key,
+  typeof nativeBigInt.key
+);
+````
+
 #### options.alwaysParseAsBig, boolean, default false
 
 Specifies if all numbers should be stored as BigNumber.

lib/parse.js

@@ -169,6 +169,24 @@ var json_parse = function (options) {
       at += 1;
       return ch;
     },
+    asBigNumber = function (v) {
+      if (BigNumber == null) {
+        BigNumber = require('bignumber.js');
+      }
+
+      var bigNum = new BigNumber(v);
+      if (!_options.useNativeBigInt) {
+        return bigNum;
+      }
+
+      if (!bigNum.isInteger()) {
+        // only case where we return BigNumber when 'useNativeBigInt' is true
+        // would only happen if parsing a very big decimal number
+        return bigNum
+      }
+
+      return BigInt(bigNum.toFixed());
+    },
     number = function () {
       // Parse a number value.
 
@@ -205,21 +223,16 @@ var json_parse = function (options) {
       if (!isFinite(number)) {
         error('Bad number');
       } else {
-        if (BigNumber == null) BigNumber = require('bignumber.js');
         //if (number > 9007199254740992 || number < -9007199254740992)
         // Bignumber has stricter check: everything with length > 15 digits disallowed
         if (string.length > 15)
           return _options.storeAsString
             ? string
-            : _options.useNativeBigInt
-            ? BigInt(string)
-            : new BigNumber(string);
+            : asBigNumber(string);
         else
           return !_options.alwaysParseAsBig
             ? number
-            : _options.useNativeBigInt
-            ? BigInt(number)
-            : new BigNumber(number);
+            : asBigNumber(number);
       }
     },
     string = function () {

package.json

@@ -29,6 +29,7 @@
   },
   "devDependencies": {
     "chai": "4.2.0",
+    "fast-check": "^2.6.0",
     "mocha": "8.0.1"
   }
 }

test/bigint-parse-test.js

@@ -2,6 +2,7 @@ var mocha = require('mocha')
   , assert = require('chai').assert
   , expect = require('chai').expect
   , BigNumber = require('bignumber.js')
+  , fc = require('fast-check')
   ;
 
 describe("Testing native BigInt support: parse", function () {
@@ -56,4 +57,14 @@ describe("Testing native BigInt support: parse", function () {
     expect(output).to.equal(input);
     done();
   });
+
+  it("Should show JSONbig does support native Bigint parse/stringify roundtrip with any valid JSON value", function (done) {
+    var JSONbig = require('../index')({
+      "useNativeBigInt": true
+    });
+    fc.assert(fc.property(fc.jsonObject(), (v) => {
+      JSONbig.parse(JSONbig.stringify(v))
+    }));
+    done();
+  });
 });

test/bigint-test.js

@@ -2,6 +2,7 @@ var mocha  = require('mocha')
   , assert = require('chai').assert
   , expect = require('chai').expect
   , BigNumber = require('bignumber.js')
+  , fc = require('fast-check')
   ;
 
 describe("Testing bigint support", function(){
@@ -28,4 +29,12 @@ describe("Testing bigint support", function(){
         expect(output).to.equal(input);
         done();
     });
+
+    it("Should show JSONbig does support bigint parse/stringify roundtrip with any valid JSON value", function (done) {
+        var JSONbig = require('../index');
+        fc.assert(fc.property(fc.jsonObject(), (v) => {
+            JSONbig.parse(JSONbig.stringify(v))
+        }));
+        done();
+    });
 });