feat: support passing BigInt argument (#355)

Author: Dunqing

bignumber.d.ts

@@ -324,7 +324,7 @@ export namespace BigNumber {
   type Constructor = typeof BigNumber;
   type ModuloMode = 0 | 1 | 3 | 6 | 9;
   type RoundingMode = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8;
-  type Value = string | number | Instance;
+  type Value = string | number | Instance | BigInt;
 }
 
 export declare class BigNumber implements BigNumber.Instance {

test/methods/BigNumber.js

@@ -79,7 +79,10 @@ Test('bigNumber', function () {
     tx(function () {new BigNumber('+.Infinity')}, "+.Infinity");
 
     t('0', new BigNumber(0));
+    t('0', new BigNumber(0n));
+    t('0', new BigNumber(BigInt(0)));
     t('0', new BigNumber(-0));
+    t('0', new BigNumber(-0n));
     t('0', new BigNumber('.0'));
     t('0', new BigNumber('0.'));
     t('0', new BigNumber('-0.'));