1 files changed, 6 insertions, 1 deletions
diff --git a/packages/abi-gen/src/utils.ts b/packages/abi-gen/src/utils.ts
index 524c54a5e..f6291d98d 100644
--- a/packages/abi-gen/src/utils.ts
+++ b/packages/abi-gen/src/utils.ts
@@ -11,7 +11,9 @@ export const utils = {
         if (solType.match(trailingArrayRegex)) {
             const arrayItemSolType = solType.replace(trailingArrayRegex, '');
             const arrayItemTsType = utils.solTypeToTsType(paramKind, arrayItemSolType);
-            const arrayTsType = `(${arrayItemTsType})[]`;
+            const arrayTsType = utils.isUnionType(arrayItemTsType)
+                ? `Array<${arrayItemTsType}>`
+                : `${arrayItemTsType}[]`;
             return arrayTsType;
         } else {
             const solTypeRegexToTsType = [
@@ -38,6 +40,9 @@ export const utils = {
             throw new Error(`Unknown Solidity type found: ${solType}`);
         }
     },
+    isUnionType(tsType: string): boolean {
+        return tsType === 'number|BigNumber';
+    },
     log(...args: any[]): void {
         console.log(...args); // tslint:disable-line:no-console
     },