From da4648374a3ed61cd94bf7c45a5a2c65b5574207 Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@warta.it>
Date: Tue, 11 Aug 2020 09:03:22 +0200
Subject: [PATCH] Add parseBankToken/parseBankTokens

---
 packages/faucet/src/tokens.spec.ts | 70 ++++++++++++++++++++++++++++++
 packages/faucet/src/tokens.ts      | 25 +++++++++++
 2 files changed, 95 insertions(+)
 create mode 100644 packages/faucet/src/tokens.spec.ts

diff --git a/packages/faucet/src/tokens.spec.ts b/packages/faucet/src/tokens.spec.ts
new file mode 100644
index 0000000000..d0a57ee2a0
--- /dev/null
+++ b/packages/faucet/src/tokens.spec.ts
@@ -0,0 +1,70 @@
+import { parseBankToken, parseBankTokens } from "./tokens";
+
+describe("tokens", () => {
+  describe("parseBankToken", () => {
+    it("works", () => {
+      expect(parseBankToken("COSM=10^6ucosm")).toEqual({
+        tickerSymbol: "COSM",
+        fractionalDigits: 6,
+        denom: "ucosm",
+      });
+    });
+  });
+
+  describe("parseBankTokens", () => {
+    it("works for one", () => {
+      expect(parseBankTokens("COSM=10^6ucosm")).toEqual([
+        {
+          tickerSymbol: "COSM",
+          fractionalDigits: 6,
+          denom: "ucosm",
+        },
+      ]);
+    });
+
+    it("works for two", () => {
+      expect(parseBankTokens("COSM=10^6ucosm,STAKE=10^3mstake")).toEqual([
+        {
+          tickerSymbol: "COSM",
+          fractionalDigits: 6,
+          denom: "ucosm",
+        },
+        {
+          tickerSymbol: "STAKE",
+          fractionalDigits: 3,
+          denom: "mstake",
+        },
+      ]);
+    });
+
+    it("ignores whitespace", () => {
+      expect(parseBankTokens("COSM=10^6ucosm, STAKE=10^3mstake\n")).toEqual([
+        {
+          tickerSymbol: "COSM",
+          fractionalDigits: 6,
+          denom: "ucosm",
+        },
+        {
+          tickerSymbol: "STAKE",
+          fractionalDigits: 3,
+          denom: "mstake",
+        },
+      ]);
+    });
+
+    it("ignores empty elements", () => {
+      expect(parseBankTokens("COSM=10^6ucosm,STAKE=10^3mstake,")).toEqual([
+        {
+          tickerSymbol: "COSM",
+          fractionalDigits: 6,
+          denom: "ucosm",
+        },
+        {
+          tickerSymbol: "STAKE",
+          fractionalDigits: 3,
+          denom: "mstake",
+        },
+      ]);
+    });
+  });
+});
diff --git a/packages/faucet/src/tokens.ts b/packages/faucet/src/tokens.ts
index c2d88a722d..011e861dd9 100644
--- a/packages/faucet/src/tokens.ts
+++ b/packages/faucet/src/tokens.ts
@@ -1,3 +1,5 @@
+import { Uint53 } from "@cosmjs/math";
+
 export interface BankTokenMeta {
   readonly denom: string;
   /**
@@ -15,3 +17,26 @@ export interface BankTokenMeta {
    */
   readonly fractionalDigits: number;
 }
+
+const parseBankTokenPattern = /^([a-zA-Z]{2,20})=10\^([0-9]+)([a-zA-Z]{2,20})$/;
+
+export function parseBankToken(input: string): BankTokenMeta {
+  const match = input.match(parseBankTokenPattern);
+  if (!match) {
+    throw new Error("Token could not be parsed. Format: DISPLAY=10^DIGITSbase, e.g. ATOM=10^6uatom");
+  }
+  return {
+    tickerSymbol: match[1],
+    fractionalDigits: Uint53.fromString(match[2]).toNumber(),
+    denom: match[3],
+  };
+}
+
+export function parseBankTokens(input: string): BankTokenMeta[] {
+  return input
+    .trim()
+    .split(",")
+    .map((part) => part.trim())
+    .filter((part) => part !== "")
+    .map((part) => parseBankToken(part));
+}