From 6f22e00488dc1ffeb5ff3400465fdefef978ad99 Mon Sep 17 00:00:00 2001
From: Tien Nguyen Khac <tiennguyenkhac1702@gmail.com>
Date: Wed, 22 Jun 2022 12:05:34 +1200
Subject: [PATCH] Fix `Decimal` can be constructed with a negative atomics

---
 packages/math/src/decimal.spec.ts | 4 ++++
 packages/math/src/decimal.ts      | 8 +++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/packages/math/src/decimal.spec.ts b/packages/math/src/decimal.spec.ts
index 52b876f7..446c8ce1 100644
--- a/packages/math/src/decimal.spec.ts
+++ b/packages/math/src/decimal.spec.ts
@@ -31,6 +31,10 @@ describe("Decimal", () => {
       expect(Decimal.fromAtomics("44", 3).toString()).toEqual("0.044");
       expect(Decimal.fromAtomics("44", 4).toString()).toEqual("0.0044");
     });
+
+    it("throws for atomics that are not non-negative", () => {
+      expect(() => Decimal.fromAtomics("-1", 0)).toThrowError(/atomics must not be negative/i);
+    });
   });
 
   describe("fromUserInput", () => {
diff --git a/packages/math/src/decimal.ts b/packages/math/src/decimal.ts
index 91ec2cc1..a0012a2e 100644
--- a/packages/math/src/decimal.ts
+++ b/packages/math/src/decimal.ts
@@ -107,8 +107,14 @@ export class Decimal {
   };
 
   private constructor(atomics: string, fractionalDigits: number) {
+    const _atomics = new BN(atomics);
+
+    if (_atomics.isNeg()) {
+      throw new Error("Atomics must not be negative");
+    }
+
     this.data = {
-      atomics: new BN(atomics),
+      atomics: _atomics,
       fractionalDigits: fractionalDigits,
     };
   }