Add methods to easily detect transaction type based on gas fields (#11382)

shared/modules/transaction.utils.js

@@ -1,6 +1,40 @@
+import { isHexString } from 'ethereumjs-util';
+
 export function transactionMatchesNetwork(transaction, chainId, networkId) {
   if (typeof transaction.chainId !== 'undefined') {
     return transaction.chainId === chainId;
   }
   return transaction.metamaskNetworkId === networkId;
 }
+
+/**
+ * Determines if the maxFeePerGas and maxPriorityFeePerGas fields are supplied
+ * and valid inputs. This will return false for non hex string inputs.
+ * @param {import("../constants/transaction").TransactionMeta} transaction -
+ *  the transaction to check
+ * @returns {boolean} true if transaction uses valid EIP1559 fields
+ */
+export function isEIP1559Transaction(transaction) {
+  return (
+    isHexString(transaction.txParams.maxFeePerGas) &&
+    isHexString(transaction.txParams.maxPriorityFeePerGas)
+  );
+}
+
+/**
+ * Determine if the maxFeePerGas and maxPriorityFeePerGas fields are not
+ * supplied and that the gasPrice field is valid if it is provided. This will
+ * return false if gasPrice is a non hex string.
+ * @param {import("../constants/transaction").TransactionMeta} transaction -
+ *  the transaction to check
+ * @returns {boolean} true if transaction uses valid Legacy fields OR lacks
+ *  EIP1559 fields
+ */
+export function isLegacyTransaction(transaction) {
+  return (
+    typeof transaction.txParams.maxFeePerGas === 'undefined' &&
+    typeof transaction.txParams.maxPriorityFeePerGas === 'undefined' &&
+    (typeof transaction.txParams.gasPrice === 'undefined' ||
+      isHexString(transaction.txParams.gasPrice))
+  );
+}

shared/modules/transaction.utils.test.js

@@ -0,0 +1,83 @@
+import { isEIP1559Transaction, isLegacyTransaction } from './transaction.utils';
+
+describe('Transaction.utils', function () {
+  describe('isEIP1559Transaction', function () {
+    it('should return true if both maxFeePerGas and maxPriorityFeePerGas are hex strings', () => {
+      expect(
+        isEIP1559Transaction({
+          txParams: { maxFeePerGas: '0x1', maxPriorityFeePerGas: '0x1' },
+        }),
+      ).toBe(true);
+    });
+
+    it('should return false if either maxFeePerGas and maxPriorityFeePerGas are non-hex strings', () => {
+      expect(
+        isEIP1559Transaction({
+          txParams: { maxFeePerGas: 0, maxPriorityFeePerGas: '0x1' },
+        }),
+      ).toBe(false);
+      expect(
+        isEIP1559Transaction({
+          txParams: { maxFeePerGas: '0x1', maxPriorityFeePerGas: 'fail' },
+        }),
+      ).toBe(false);
+    });
+
+    it('should return false if either maxFeePerGas or maxPriorityFeePerGas are not supplied', () => {
+      expect(
+        isEIP1559Transaction({
+          txParams: { maxPriorityFeePerGas: '0x1' },
+        }),
+      ).toBe(false);
+      expect(
+        isEIP1559Transaction({
+          txParams: { maxFeePerGas: '0x1' },
+        }),
+      ).toBe(false);
+    });
+  });
+
+  describe('isLegacyTransaction', function () {
+    it('should return true if no gas related fields are supplied', () => {
+      expect(
+        isLegacyTransaction({
+          txParams: {},
+        }),
+      ).toBe(true);
+    });
+
+    it('should return true if gasPrice is solely provided', () => {
+      expect(
+        isLegacyTransaction({
+          txParams: { gasPrice: '0x1' },
+        }),
+      ).toBe(true);
+    });
+
+    it('should return false if gasPrice is not a hex string', () => {
+      expect(
+        isLegacyTransaction({
+          txParams: { gasPrice: 100 },
+        }),
+      ).toBe(false);
+    });
+
+    it('should return false if either maxFeePerGas or maxPriorityFeePerGas are supplied', () => {
+      expect(
+        isLegacyTransaction({
+          txParams: {
+            maxFeePerGas: '0x1',
+          },
+        }),
+      ).toBe(false);
+
+      expect(
+        isLegacyTransaction({
+          txParams: {
+            maxPriorityFeePerGas: 'any data',
+          },
+        }),
+      ).toBe(false);
+    });
+  });
+});