diff --git a/lib/util/propTypes.js b/lib/util/propTypes.js
index 89be4d820b..c19978587c 100644
--- a/lib/util/propTypes.js
+++ b/lib/util/propTypes.js
@@ -290,7 +290,7 @@ module.exports = function propTypesInstructions(context, components, utils) {
       }
       // the game here is to find the type declaration in the code
       const candidateTypes = context.getSourceCode().ast.body.filter((item) => item.type === 'VariableDeclaration' && item.kind === 'type');
-      const declarations = Array.prototype.flatMap(candidateTypes, (type) => type.declarations);
+      const declarations = flatMap(candidateTypes, (type) => type.declarations);
 
       // we tried to find either an interface or a type with the TypeReference name
       const typeDeclaration = declarations.find((dec) => dec.id.name === typeName);