Merge pull request #36 from babyadoresorange/master

use native BigInt as option, add always option

Author: sidorares

README.md

@@ -4,7 +4,9 @@ json-bigint
 [![Build Status](https://secure.travis-ci.org/sidorares/json-bigint.png)](http://travis-ci.org/sidorares/json-bigint)
 [![NPM](https://nodei.co/npm/json-bigint.png?downloads=true&stars=true)](https://nodei.co/npm/json-bigint/)
 
-JSON.parse/stringify with bigints support. Based on Douglas Crockford [JSON.js](https://github.com/douglascrockford/JSON-js) package and [bignumber.js](https://github.com/MikeMcl/bignumber.js) library.
+JSON.parse/stringify with bigints support. Based on Douglas Crockford [JSON.js](https://github.com/douglascrockford/JSON-js) package and [bignumber.js](https://github.com/MikeMcl/bignumber.js) library. 
+
+Native `Bigint` was added to JS recently, so we added an option to leverage it instead of `bignumber.js`. However, the parsing with native `BigInt` is kept an option for backward compability.
 
 While most JSON parsers assume numeric values have same precision restrictions as IEEE 754 double, JSON specification _does not_ say anything about number precision. Any floating point number in decimal (optionally scientific) notation is valid JSON value. It's a good idea to serialize values which might fall out of IEEE 754 integer precision as strings in your JSON api, but `{ "value" : 9223372036854775807}`, for example, is still a valid RFC4627 JSON string, and in most JS runtimes the result of `JSON.parse` is this object: `{ value: 9223372036854776000 }`
 
@@ -107,6 +109,61 @@ Default type: object, With option type: string
 
 ```
 
+#### options.useNativeBigInt, boolean, default false
+Specifies if parser uses native BigInt instead of bignumber.js
+
+example:
+```js
+var JSONbig = require('json-bigint');
+var JSONbigNative = require('json-bigint')({"useNativeBigInt": true});
+var key = '{ "key": 993143214321423154315154321 }';
+console.log(`\n\nStoring the Number as native BigInt, instead of 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);
+
+```
+
+Output
+```
+Storing the Number as native BigInt, instead of a BigNumber
+Input: { "key": 993143214321423154315154321 }
+Default type: object, With option type: bigint 
+
+```
+
+#### options.alwaysParseAsBig, boolean, default false
+Specifies if all numbers should be stored as BigNumber.
+
+Note that this is a dangerous behavior as it breaks the default functionality of being able to convert back-and-forth without data type changes (as this will convert all Number to be-and-stay BigNumber)
+
+example:
+```js
+var JSONbig = require('json-bigint');
+var JSONbigAlways = require('json-bigint')({"alwaysParseAsBig": true});
+var key = '{ "key": 123 }'; // there is no need for BigNumber by default, but we're forcing it
+console.log(`\n\nStoring the Number as a BigNumber, instead of a Number`);
+console.log('Input:', key);
+var normal = JSONbig.parse(key);
+var always = JSONbigAlways.parse(key);
+console.log('Default type: %s, With option type: %s', typeof normal.key, typeof always.key);
+
+```
+
+Output
+```
+Storing the Number as a BigNumber, instead of a Number
+Input: { "key": 123 }
+Default type: number, With option type: object
+
+```
+
+If you want to force all numbers to be parsed as native `BigInt`
+(you probably do! Otherwise any calulations become a real headache):
+```js
+var JSONbig = require('json-bigint')({"alwaysParseAsBig": true, "useNativeBigInt": true});
+```
 
 ### Links:
 - [RFC4627: The application/json Media Type for JavaScript Object Notation (JSON)](http://www.ietf.org/rfc/rfc4627.txt)
@@ -115,3 +172,20 @@ Default type: object, With option type: string
 - [What is JavaScript's Max Int? What's the highest Integer value a Number can go to without losing precision?](http://stackoverflow.com/questions/307179/what-is-javascripts-max-int-whats-the-highest-integer-value-a-number-can-go-t)
 - [Large numbers erroneously rounded in Javascript](http://stackoverflow.com/questions/1379934/large-numbers-erroneously-rounded-in-javascript)
 
+### Note on native BigInt support
+
+#### Stringifying
+Full support out-of-the-box, stringifies BigInts as pure numbers (no quotes, no `n`)
+
+#### Limitations
+- Roundtrip operations
+
+`s === JSONbig.stringify(JSONbig.parse(s))` but
+
+`o !== JSONbig.parse(JSONbig.stringify(o))` 
+
+when `o` has a value with something like `123n`. 
+
+`JSONbig` stringify `123n` as `123`, which becomes `number` (aka `123` not `123n`) by default when being reparsed. 
+
+There is currently no consistent way to deal with this issue, so we decided to leave it, handling this specific case is then up to users.

lib/parse.js

@@ -76,7 +76,9 @@ var json_parse = function (options) {
 // Default options one can override by passing options to the parse()
     var _options = {
         "strict": false,  // not being strict means do not generate syntax errors for "duplicate key"
-        "storeAsString": false // toggles whether the values should be stored as BigNumber (default) or a string
+        "storeAsString": false, // toggles whether the values should be stored as BigNumber (default) or a string
+        "alwaysParseAsBig": false, // toggles whether all numbers should be Big
+        "useNativeBigInt": false // toggles whether to use native BigInt instead of bignumber.js
     };
 
 
@@ -88,6 +90,8 @@ var json_parse = function (options) {
         if (options.storeAsString === true) {
             _options.storeAsString = true;
         }
+        _options.alwaysParseAsBig = options.alwaysParseAsBig === true ? options.alwaysParseAsBig : false
+        _options.useNativeBigInt = options.useNativeBigInt === true ? options.useNativeBigInt : false
     }
 
 
@@ -174,8 +178,9 @@ var json_parse = function (options) {
                 //if (number > 9007199254740992 || number < -9007199254740992)
                 // Bignumber has stricter check: everything with length > 15 digits disallowed
                 if (string.length > 15)
-                   return (_options.storeAsString === true) ? string : new BigNumber(string);
-                return number;
+                  return _options.storeAsString ? string : _options.useNativeBigInt ? BigInt(string) : new BigNumber(string);
+                else
+                  return !_options.alwaysParseAsBig ? number : _options.useNativeBigInt ? BigInt(number) : new BigNumber(number);
             }
         },
 
@@ -191,12 +196,17 @@ var json_parse = function (options) {
 // When parsing for string values, we must look for " and \ characters.
 
             if (ch === '"') {
+                var startAt = at;
                 while (next()) {
                     if (ch === '"') {
+                        if (at - 1 > startAt)
+                            string += text.substring(startAt, at - 1);
                         next();
                         return string;
                     }
                     if (ch === '\\') {
+                        if (at - 1 > startAt)
+                            string += text.substring(startAt, at - 1);
                         next();
                         if (ch === 'u') {
                             uffff = 0;
@@ -213,8 +223,7 @@ var json_parse = function (options) {
                         } else {
                             break;
                         }
-                    } else {
-                        string += ch;
+                        startAt = at;
                     }
                 }
             }

lib/stringify.js

@@ -249,6 +249,7 @@ var JSON = module.exports;
 
         case 'boolean':
         case 'null':
+        case 'bigint':
 
 // If the value is a boolean or null, convert it to a string. Note:
 // typeof null does not produce 'null'. The case is included here in

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "json-bigint",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "JSON.parse with bigints support",
   "main": "index.js",
   "scripts": {
@@ -26,4 +26,4 @@
     "chai": "~1.9.1",
     "mocha": "~1.20.1"
   }
-}
+}