Add support for big numbers

README.md

@@ -91,6 +91,10 @@ client.getInfo().then(([body, headers]) => console.log(body, headers));
 const [body, headers] = await client.getInfo();
 ```
 
+### Floating point number precision in JavaScript
+
+Due to [Javascript floating point precision](http://floating-point-gui.de/), to prevent precision loss when using `bitcoin-core` we should pass all big numbers (numbers with more than 15 significant digits) as string instead of using `Number` data type.
+
 ### Version Checking
 By default, all methods are exposed on the client independently of the version it is connecting to. This is the most flexible option as defining methods for unavailable RPC calls does not cause any harm and the library is capable of handling a `Method not found` response error correctly.
 

package.json

@@ -36,6 +36,7 @@
   },
   "dependencies": {
     "bluebird": "^3.4.1",
+    "json-bigint": "^0.2.0",
     "lodash": "^4.0.0",
     "request": "^2.53.0",
     "semver": "^5.1.0",

src/index.js

@@ -118,7 +118,8 @@ class Client {
 
       return this.request.postAsync({
         auth: _.pickBy(this.auth, _.identity),
-        body,
+        body: JSON.stringify(body),
+        json: false,
         uri: '/'
       })
       .bind(this)

src/parser.js

@@ -3,9 +3,16 @@
  * Module dependencies.
  */
 
+import JSONBigInt from 'json-bigint';
 import RpcError from './errors/rpc-error';
 import _ from 'lodash';
 
+/**
+ * JSONBigInt parser.
+ */
+
+const { parse } = JSONBigInt({ storeAsString: true, strict: true }); // eslint-disable-line new-cap
+
 /**
  * Get response result and errors.
  */
@@ -52,6 +59,9 @@ export default class Parser {
       throw new RpcError(response.statusCode);
     }
 
+    // Parsing the body with custom parser to support BigNumbers.
+    body = parse(body);
+
     if (!Array.isArray(body)) {
       return get(body, { headers: this.headers, response });
     }

test/index_test.js

@@ -199,7 +199,7 @@ describe('Client', () => {
       it('should return the proof-of-work difficulty', async () => {
         const difficulty = await new Client(config.bitcoind).getDifficulty();
 
-        difficulty.should.be.a.Number();
+        difficulty.should.be.a.String();
       });
     });