@0x/utils: Add support for nested rich revert decoding

packages/utils/src/revert_error.ts

@@ -14,6 +14,7 @@ type ArgTypes =
     | BigNumber
     | number
     | boolean
+    | RevertError
     | BigNumber[]
     | string[]
     | number[]
@@ -122,6 +123,19 @@ export abstract class RevertError extends Error {
         const instance = new type();
         try {
             const values = decoder(_bytes);
+            _.transform(
+                values,
+                (result, value, key) => {
+                    const { type: argType } = instance._getArgumentByName(key);
+                    if (argType === 'bytes') {
+                        try {
+                            const nestedRevert = RevertError.decode(value as string, coerce);
+                            result[key] = nestedRevert.toString();
+                        } catch (err) {} // tslint:disable-line:no-empty
+                    }
+                },
+                values,
+            );
             _.assign(instance, { values });
             instance.message = instance.toString();
             return instance;

packages/utils/test/revert_error_test.ts

@@ -39,7 +39,14 @@ class FixedSizeArrayRevertError extends RevertError {
     }
 }
 
+class ParentRevertError extends RevertError {
+    public constructor(nestedError?: string) {
+        super('ParentRevertError', 'ParentRevertError(bytes nestedError)', { nestedError });
+    }
+}
+
 RevertError.registerType(CustomRevertError);
+RevertError.registerType(ParentRevertError);
 
 describe('RevertError', () => {
     describe('equality', () => {
@@ -159,6 +166,12 @@ describe('RevertError', () => {
             const decode = () => RevertError.decode(_encoded);
             expect(decode).to.throw();
         });
+        it('should decode a nested revert error', () => {
+            const nested = new StringRevertError(message);
+            const parent = new ParentRevertError(nested.encode());
+            const decoded = RevertError.decode(parent.encode());
+            expect(decoded.toString()).to.equal(new ParentRevertError(nested.toString()).toString());
+        });
     });
     describe('getThrownErrorRevertErrorBytes', () => {
         it('should decode Parity revert errors', () => {