IBM · akoenig · Apr 17, 2020 · May 13, 2020
diff --git a/packages/openapi-to-graphql-cli/package-lock.json b/packages/openapi-to-graphql-cli/package-lock.json
diff --git a/packages/openapi-to-graphql/lib/oas_3_tools.js b/packages/openapi-to-graphql/lib/oas_3_tools.js
diff --git a/packages/openapi-to-graphql/lib/oas_3_tools.js.map b/packages/openapi-to-graphql/lib/oas_3_tools.js.map
diff --git a/packages/openapi-to-graphql/lib/resolver_builder.js b/packages/openapi-to-graphql/lib/resolver_builder.js
diff --git a/packages/openapi-to-graphql/lib/resolver_builder.js.map b/packages/openapi-to-graphql/lib/resolver_builder.js.map
diff --git a/packages/openapi-to-graphql/package-lock.json b/packages/openapi-to-graphql/package-lock.json
diff --git a/packages/openapi-to-graphql/src/oas_3_tools.ts b/packages/openapi-to-graphql/src/oas_3_tools.ts
@@ -422,7 +422,18 @@ export function instantiatePathAndGetQuery(
 
           // Query parameters
           case 'query':
-            query[param.name] = args[sanitizedParamName]
+            /**
+             * Spec-compliant query string serialization:
+             * http:pec.openapis.org/oas/v3.0.3#style-examples
+             *
+             * Whenever the query string value is an array, we check if it
+             * should be `exploded`. In this case, we don't serialize anything.
+             * Otherwise, the array will be joined in comma-separated fashion.
+             */
+            const arg = args[sanitizedParamName]
+            const shouldBeCommaSeparated = Array.isArray(arg) && !param.explode
+
+            query[param.name] = shouldBeCommaSeparated ? arg.join(',') : arg
             break
 
           // Header parameters