From 1908f7fd6f646aa5d44dad5baa7c6c807efe4483 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lloren=C3=A7?= <llorenc.muntaner@dfinity.org>
Date: Fri, 26 Jan 2024 16:22:03 +0100
Subject: [PATCH] Feat: Add `toE8s` to TokenAmountV2

---
 packages/utils/src/parser/token.spec.ts | 72 +++++++++++++++++++++++++
 packages/utils/src/parser/token.ts      | 14 +++++
 2 files changed, 86 insertions(+)

diff --git a/packages/utils/src/parser/token.spec.ts b/packages/utils/src/parser/token.spec.ts
index 19f73ce68..a5eda4449 100644
--- a/packages/utils/src/parser/token.spec.ts
+++ b/packages/utils/src/parser/token.spec.ts
@@ -347,6 +347,32 @@ describe("TokenAmountV2 with 18 decimals", () => {
       FromStringToTokenError.InvalidFormat,
     );
   });
+
+  it("returns the value in e8s", () => {
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "2", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(200_000_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "0.21", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(21_000_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "0.00021", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(21_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "2000", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(200_000_000_000n);
+  });
 });
 
 describe("TokenAmountV2 with 2 decimals", () => {
@@ -393,6 +419,26 @@ describe("TokenAmountV2 with 2 decimals", () => {
       }),
     );
   });
+
+  it("returns the value in e8s", () => {
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "2", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(200_000_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "0.21", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(21_000_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "2000", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(200_000_000_000n);
+  });
 });
 
 describe("TokenAmountV2 with 0 decimals", () => {
@@ -472,4 +518,30 @@ describe("TokenAmountV2 with 8 decimals", () => {
       TokenAmountV2.fromUlps({ token: token, amount: 0n }),
     );
   });
+
+  it("returns the value in e8s", () => {
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "2", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(200_000_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "0.21", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(21_000_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "0.00021", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(21_000n);
+
+    expect(
+      (
+        TokenAmountV2.fromString({ amount: "2000", token }) as TokenAmountV2
+      ).toE8s(),
+    ).toEqual(200_000_000_000n);
+  });
 });
diff --git a/packages/utils/src/parser/token.ts b/packages/utils/src/parser/token.ts
index d09b7153c..266cc4df4 100644
--- a/packages/utils/src/parser/token.ts
+++ b/packages/utils/src/parser/token.ts
@@ -322,4 +322,18 @@ export class TokenAmountV2 {
   public toUlps(): bigint {
     return this.ulps;
   }
+
+  /**
+   *
+   * @returns The amount of ulps in e8s precision
+   */
+  public toE8s(): bigint {
+    if (this.token.decimals < 8) {
+      return this.ulps * 10n ** BigInt(8 - this.token.decimals);
+    } else if (this.token.decimals === 8) {
+      return this.ulps;
+    } else {
+      return this.ulps / 10n ** BigInt(this.token.decimals - 8);
+    }
+  }
 }