Merge pull request #26 from consenlabs/hotfix/bignumber_precision_bug

fix bignumber.js digits error

src/quoting.ts

@@ -35,14 +35,10 @@ export const constructQuoteResponse = (indicativePrice: IndicativePriceApiResult
 }
 
 // Process buy amount for WYSIWY
-function applyFeeToAmount(amount: number, feeFactor: number, precision: number) {
+export function applyFeeToAmount(amount: number, feeFactor: number, precision: number): number {
   if (isNil(amount)) return amount
-  return truncateAmount(
-    toBN(amount)
-      .dividedBy(1 - feeFactor / 10000)
-      .toString(),
-    precision
-  )
+  const rate = toBN(1).sub(toBN(feeFactor).div(10000))
+  return truncateAmount(toBN(amount).dividedBy(rate).toString(), precision)
 }
 
 function calcFeeFactorWhenBuy(tokenCfg: TokenConfig, factor: number | null): number {

test/quoting.spec.ts

@@ -0,0 +1,10 @@
+import 'mocha'
+import { assert } from 'chai'
+import { applyFeeToAmount } from '../src/quoting'
+
+describe('quoting.ts', function () {
+  it('applyFeeToAmount', function () {
+    const fee = applyFeeToAmount(104, 2553, 6)
+    assert.equal(fee, 139.653551)
+  })
+})