chore: calc slippage percentage

packages/bridge-controller/CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add and export `calcSlippagePercentage`, a utility that calculates the absolute slippage percentage based on the adjusted return and the sent amount ([#5723](https://github.com/MetaMask/core/pull/5723)).
+
 ### Changed
 
 - Bump `@metamask/controller-utils` to `^11.8.0` ([#5765](https://github.com/MetaMask/core/pull/5765))

packages/bridge-controller/src/index.ts

@@ -103,7 +103,11 @@ export {
   getDefaultBridgeControllerState,
 } from './utils/bridge';
 
-export { isValidQuoteRequest, formatEtaInMinutes } from './utils/quote';
+export {
+  isValidQuoteRequest,
+  formatEtaInMinutes,
+  calcSlippagePercentage,
+} from './utils/quote';
 
 export { calcLatestSrcBalance } from './utils/balance';
 

packages/bridge-controller/src/utils/quote.test.ts

@@ -14,6 +14,7 @@ import {
   calcSwapRate,
   calcCost,
   formatEtaInMinutes,
+  calcSlippagePercentage,
 } from './quote';
 import type {
   GenericQuoteRequest,
@@ -522,4 +523,40 @@ describe('Quote Metadata Utils', () => {
       expect(result.usd).toBeNull();
     });
   });
+
+  describe('calcSlippagePercentage', () => {
+    it.each([
+      ['100', '100', '100', '100', 0, 0],
+      ['95', '95', '100', '100', 5, 5],
+      ['98.3', '98.3', '100', '100', 1.7, 1.7],
+      [null, null, '100', '100', null, null],
+      ['105', '105', '100', '100', 5, 5],
+    ])(
+      'calcSlippagePercentage: calculate slippage absolute value for received amount %p, usd %p, sent amount %p, usd %p to expected amount %p, usd %p',
+      (
+        returnValueInCurrency: string | null,
+        returnUsd: string | null,
+        sentValueInCurrency: string | null,
+        sentUsd: string | null,
+        expectedValueInCurrency: number | null,
+        expectedUsd: number | null,
+      ) => {
+        const result = calcSlippagePercentage(
+          {
+            valueInCurrency: returnValueInCurrency,
+            usd: returnUsd,
+          },
+          {
+            amount: '',
+            valueInCurrency: sentValueInCurrency,
+            usd: sentUsd,
+          },
+        );
+        expect(result.percentageInCurrency).toStrictEqual(
+          expectedValueInCurrency,
+        );
+        expect(result.percentageInUsd).toStrictEqual(expectedUsd);
+      },
+    );
+  });
 });

packages/bridge-controller/src/utils/quote.ts

@@ -304,6 +304,42 @@ export const calcCost = (
       : null,
 });
 
+/**
+ * Calculates the slippage absolute value percentage based on the adjusted return and sent amount.
+ *
+ * @param adjustedReturn - Adjusted return value
+ * @param sentAmount - Sent amount value
+ * @returns the slippage in percentage
+ */
+export const calcSlippagePercentage = (
+  adjustedReturn: ReturnType<typeof calcAdjustedReturn>,
+  sentAmount: ReturnType<typeof calcSentAmount>,
+) => {
+  const cost = calcCost(adjustedReturn, sentAmount);
+  return {
+    percentageInCurrency:
+      cost.valueInCurrency && sentAmount.valueInCurrency
+        ? parseFloat(
+            new BigNumber(cost.valueInCurrency)
+              .div(sentAmount.valueInCurrency)
+              .times(100)
+              .abs()
+              .toFixed(2),
+          )
+        : null,
+    percentageInUsd:
+      cost.usd && sentAmount.usd
+        ? parseFloat(
+            new BigNumber(cost.usd)
+              .div(sentAmount.usd)
+              .times(100)
+              .abs()
+              .toFixed(2),
+          )
+        : null,
+  };
+};
+
 export const formatEtaInMinutes = (
   estimatedProcessingTimeInSeconds: number,
 ) => {