add toExact to TokenAmount

src/entities/fractions/tokenAmount.ts

 import invariant from 'tiny-invariant'
 import JSBI from 'jsbi'
+import _Big from 'big.js'
+import toFormat from 'toformat'
 
 import { BigintIsh, Rounding } from '../../types'
 import { TEN, SolidityType } from '../../constants'
@@ -7,6 +9,8 @@ import { parseBigintIsh, validateSolidityTypeInstance } from '../../utils'
 import { Token } from '../token'
 import { Fraction } from './fraction'
 
+const Big = toFormat(_Big)
+
 export class TokenAmount extends Fraction {
   public readonly token: Token
 
@@ -49,4 +53,9 @@ export class TokenAmount extends Fraction {
     invariant(decimalPlaces <= this.token.decimals, 'DECIMALS')
     return super.toFixed(decimalPlaces, format, rounding)
   }
+
+  public toExact(format: object = { groupSeparator: '' }): string {
+    Big.DP = this.token.decimals
+    return new Big(this.numerator.toString()).div(this.denominator.toString()).toFormat(format)
+  }
 }

test/entities.test.ts

@@ -173,6 +173,12 @@ describe('entities', () => {
           }
         })
       })
+
+      it('TokenAmount', () => {
+        const amount = new TokenAmount(WETH, '1234567000000000000000')
+        expect(amount.toExact()).toEqual('1234.567')
+        expect(amount.toExact({ groupSeparator: ',' })).toEqual('1,234.567')
+      })
     })
   })
 })