Throw revert reasons from contract wrappers

2 files changed, 17 insertions, 0 deletions

diff --git a/packages/base-contract/CHANGELOG.json b/packages/base-contract/CHANGELOG.json
index fba072011..b97bc00e0 100644
--- a/packages/base-contract/CHANGELOG.json
+++ b/packages/base-contract/CHANGELOG.json
@@ -5,6 +5,10 @@
             {
                 "note": "Change the way we detect BN to work with the newest ethers.js",
                 "pr": 1069
+            },
+            {
+                "note": "Add baseContract._throwIfRevertWithReasonCallResult",
+                "pr": 1069
             }
         ]
     },
diff --git a/packages/base-contract/src/index.ts b/packages/base-contract/src/index.ts
index 90e576c24..538c87431 100644
--- a/packages/base-contract/src/index.ts
+++ b/packages/base-contract/src/index.ts
@@ -20,6 +20,10 @@ export interface EthersInterfaceByFunctionSignature {
     [key: string]: ethers.Interface;
 }
 
+const REVERT_ERROR_SELECTOR = '08c379a0';
+const REVERT_ERROR_SELECTOR_OFFSET = 2;
+const REVERT_ERROR_SELECTOR_END = 10;
+
 export class BaseContract {
     protected _ethersInterfacesByFunctionSignature: EthersInterfaceByFunctionSignature;
     protected _web3Wrapper: Web3Wrapper;
@@ -82,6 +86,15 @@ export class BaseContract {
         }
         return txDataWithDefaults;
     }
+    protected static _throwIfRevertWithReasonCallResult(rawCallResult: string): void {
+        if (rawCallResult.slice(REVERT_ERROR_SELECTOR_OFFSET, REVERT_ERROR_SELECTOR_END) === REVERT_ERROR_SELECTOR) {
+            const revertReason = ethers.utils.defaultAbiCoder.decode(
+                ['string'],
+                ethers.utils.hexDataSlice(rawCallResult, 4),
+            );
+            throw new Error(revertReason);
+        }
+    }
     // Throws if the given arguments cannot be safely/correctly encoded based on
     // the given inputAbi. An argument may not be considered safely encodeable
     // if it overflows the corresponding Solidity type, there is a bug in the