launchpad: Update GasPrice to hold Decimal

packages/launchpad/src/gas.spec.ts

@@ -1,9 +1,23 @@
+import { Decimal } from "@cosmjs/math";
+
 import { GasPrice } from "./gas";
 
 describe("GasPrice", () => {
   it("can be constructed", () => {
-    const gasPrice = new GasPrice(3.14, "utest");
-    expect(gasPrice.amount).toEqual(3.14);
-    expect(gasPrice.denom).toEqual("utest");
+    const inputs = ["3.14", "3", "0.14"];
+    inputs.forEach((input) => {
+      const gasPrice = new GasPrice(Decimal.fromUserInput(input, 18), "utest");
+      expect(gasPrice.amount.toString()).toEqual(input);
+      expect(gasPrice.denom).toEqual("utest");
+    });
+  });
+
+  it("can be constructed from a config string", () => {
+    const inputs = ["3.14", "3", "0.14"];
+    inputs.forEach((input) => {
+      const gasPrice = GasPrice.fromString(`${input}utest`);
+      expect(gasPrice.amount.toString()).toEqual(input);
+      expect(gasPrice.denom).toEqual("utest");
+    });
   });
 });

packages/launchpad/src/gas.ts

@@ -1,14 +1,30 @@
+import { Decimal } from "@cosmjs/math";
+
 import { coins } from "./coins";
 import { StdFee } from "./types";
 
 export class GasPrice {
-  public readonly amount: number;
+  public readonly amount: Decimal;
   public readonly denom: string;
 
-  constructor(amount: number, denom: string) {
+  constructor(amount: Decimal, denom: string) {
     this.amount = amount;
     this.denom = denom;
   }
+
+  public static fromString(gasPrice: string): GasPrice {
+    const matchResult = gasPrice.match(/^(?<amount>.+?)(?<denom>[a-z]+)$/);
+    if (!matchResult) {
+      throw new Error("Invalid gas price string");
+    }
+    const { amount, denom } = matchResult.groups as { readonly amount: string; readonly denom: string };
+    if (denom.length < 3 || denom.length > 127) {
+      throw new Error("Gas price denomination must be between 3 and 127 characters");
+    }
+    const fractionalDigits = 18;
+    const decimalAmount = Decimal.fromUserInput(amount, fractionalDigits);
+    return new GasPrice(decimalAmount, denom);
+  }
 }
 
 export type GasLimits<T extends Record<string, StdFee>> = {
@@ -16,7 +32,8 @@ export type GasLimits<T extends Record<string, StdFee>> = {
 };
 
 function calculateFee(gasLimit: number, { denom, amount: gasPriceAmount }: GasPrice): StdFee {
-  const amount = Math.ceil(gasPriceAmount * gasLimit);
+  const gasLimitDecimal = Decimal.fromUserInput(gasLimit.toString(), gasPriceAmount.fractionalDigits);
+  const amount = Math.ceil(gasPriceAmount.multiply(gasLimitDecimal).toFloatApproximation());
   return {
     amount: coins(amount, denom),
     gas: gasLimit.toString(),

packages/launchpad/types/gas.d.ts

@@ -1,8 +1,10 @@
+import { Decimal } from "@cosmjs/math";
 import { StdFee } from "./types";
 export declare class GasPrice {
-  readonly amount: number;
+  readonly amount: Decimal;
   readonly denom: string;
-  constructor(amount: number, denom: string);
+  constructor(amount: Decimal, denom: string);
+  static fromString(gasPrice: string): GasPrice;
 }
 export declare type GasLimits<T extends Record<string, StdFee>> = {
   readonly [key in keyof T]: number;