Develop

src/util.ts

@@ -742,7 +742,8 @@ export async function prepareXchainFromAmountCalculation({
 		const slippageFractionBN = ethers.BigNumber.from(Math.floor(slippagePercentage * 1000))
 		const slippageBN = fromAmountBN.mul(slippageFractionBN).div(100000) // 1000 * 100 (10e5)
 		const totalFromAmountBN = fromAmountBN.add(slippageBN)
-		return ethers.utils.formatUnits(totalFromAmountBN, fromToken.decimals)
+		const amount = ethers.utils.formatUnits(totalFromAmountBN, normalizedDecimalCount)
+		return stringToFixed(amount, fromToken.decimals)
 	} catch (error) {
 		console.error('Failed to calculate fromAmount:', error)
 		return null
@@ -759,3 +760,12 @@ export function normalizePath(url: string): string {
 		return url.replace(/\/+/g, '/')
 	}
 }
+
+export function stringToFixed(numStr: string, precision: number = 0): string {
+	const match = numStr.match(/^(-?\d+)\.(?<decimals>\d*)$/)
+	if (!match) return numStr
+
+	const [_, intPart, decimals] = match
+	const rounded = decimals.padEnd(precision, '0').slice(0, precision)
+	return rounded ? `${intPart}.${rounded}` : intPart
+}

test/unit/util.test.ts

@@ -1,4 +1,6 @@
-import { normalizePath } from '../../src/util'
+import { normalizePath, prepareXchainFromAmountCalculation, stringToFixed } from '../../src/util'
+
+const mockFetch = jest.fn()
 
 describe('util', () => {
 	describe('normalizePath', () => {
@@ -14,4 +16,69 @@ describe('util', () => {
 			expect(normalizePath(url)).toBe(normalizedUrl)
 		})
 	})
+
+	describe('prepareXchainFromAmountCalculation', () => {
+		beforeEach(() => {
+			jest.spyOn(global, 'fetch').mockImplementation(mockFetch)
+		})
+
+		afterEach(() => {
+			jest.restoreAllMocks()
+			jest.clearAllMocks()
+		})
+		it('should return price with correct decimals', async () => {
+			const fromToken = {
+				chainId: '534352',
+				address: '0x06efdbff2a14a7c8e15944d1f4a48f9f95f663a4',
+				decimals: 6,
+			}
+			const toToken = {
+				chainId: '8453',
+				address: '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE',
+				decimals: 18,
+			}
+			const fromTokenPrice = 0.999842
+			const toTokenPrice = 2453.66
+			const toAmount = '0.00408'
+			const expectedFromAmount = '10.042552'
+			const slippagePercentage = 0.3
+			mockFetch.mockImplementation((url: string) => {
+				const tokenAddress = new URL(url).searchParams.get('tokenAddress')
+				let price: number
+				if (tokenAddress === fromToken.address) {
+					price = fromTokenPrice
+				} else if (tokenAddress === toToken.address) {
+					price = toTokenPrice
+				} else {
+					price = 0
+				}
+				return Promise.resolve({
+					json: () => Promise.resolve({ price }),
+				})
+			})
+
+			const fromAmount = await prepareXchainFromAmountCalculation({
+				fromToken,
+				toToken,
+				toAmount,
+				slippagePercentage,
+			})
+
+			expect(mockFetch).toHaveBeenCalledTimes(2)
+			expect(fromAmount).toBe(expectedFromAmount)
+		})
+	})
+
+	describe('stringToFixed', () => {
+		it.each([
+			['0.001', '0.00', 2],
+			['0.01', '0.01', 2],
+			['0.1', '0.10', 2],
+			['1', '1', 2],
+			['10.1', '10.10', 2],
+			['10.123456', '10.123', 3],
+		])('should convert %s to %s with precision %s', (numStr, expected, precision) => {
+			expect(stringToFixed(numStr, precision)).toBe(expected)
+		})
+	})
 })