diff --git a/Sources/Apollo/GraphQLSelectionSetMapper.swift b/Sources/Apollo/GraphQLSelectionSetMapper.swift
index 485daff287..ab16032a11 100644
--- a/Sources/Apollo/GraphQLSelectionSetMapper.swift
+++ b/Sources/Apollo/GraphQLSelectionSetMapper.swift
@@ -9,6 +9,10 @@ public final class GraphQLSelectionSetMapper<T: SelectionSet>: GraphQLResultAccu
 
   let dataDictMapper: DataDictMapper
 
+  public init(dataDictMapper: DataDictMapper) {
+    self.dataDictMapper = dataDictMapper
+  }
+
   public var requiresCacheKeyComputation: Bool {
     dataDictMapper.requiresCacheKeyComputation
   }