diff --git a/src/language-js/utils.js b/src/language-js/utils.js
index 2849d0298..841a21014 100644
--- a/src/language-js/utils.js
+++ b/src/language-js/utils.js
@@ -430,45 +430,59 @@ function isMemberish(node) {
   );
 }
 
-const simpleFlowTypeAnnotations = new Set([
+const simpleTypeAnnotations = new Set([
+  // `any`
   "AnyTypeAnnotation",
+  "TSAnyKeyword",
+  // `null`
   "NullLiteralTypeAnnotation",
-  "GenericTypeAnnotation",
+  "TSNullKeyword",
+  // `this`
   "ThisTypeAnnotation",
+  "TSThisType",
+  // `number`
   "NumberTypeAnnotation",
+  "TSNumberKeyword",
+  // `void`
   "VoidTypeAnnotation",
-  "EmptyTypeAnnotation",
-  "MixedTypeAnnotation",
+  "TSVoidKeyword",
+  // `boolean`
   "BooleanTypeAnnotation",
+  "TSBooleanKeyword",
+  // `bigint`
+  "BigIntTypeAnnotation",
+  "TSBigIntKeyword",
+  // literals
   "BooleanLiteralTypeAnnotation",
   "StringTypeAnnotation",
-  "BigIntTypeAnnotation",
   "BigIntLiteralTypeAnnotation",
-]);
-const simpleTypeScriptTypeAnnotations = new Set([
-  "TSAnyKeyword",
-  "TSNullKeyword",
-  "TSTypeReference",
-  "TSThisType",
-  "TSNumberKeyword",
-  "TSVoidKeyword",
-  "TSBooleanKeyword",
-  "TSBigIntKeyword",
   "TSLiteralType",
+  // flow only, `empty`, `mixed`
+  "EmptyTypeAnnotation",
+  "MixedTypeAnnotation",
 ]);
-
 /**
  * @param {Node} node
  * @returns {boolean}
  */
 function isSimpleType(node) {
-  return (
-    node &&
-    ((simpleFlowTypeAnnotations.has(node.type) &&
-      !(node.type === "GenericTypeAnnotation" && node.typeParameters)) ||
-      (simpleTypeScriptTypeAnnotations.has(node.type) &&
-        !(node.type === "TSTypeReference" && node.typeParameters)))
-  );
+  if (!node) {
+    return false;
+  }
+
+  if (
+    (node.type === "GenericTypeAnnotation" ||
+      node.type === "TSTypeReference") &&
+    !node.typeParameters
+  ) {
+    return true;
+  }
+
+  if (simpleTypeAnnotations.has(node.type)) {
+    return true;
+  }
+
+  return false;
 }
 
 const unitTestRe = /^(skip|[fx]?(it|describe|test))$/;
diff --git a/tests/typescript/typeparams/consistent/__snapshots__/jsfmt.spec.js.snap b/tests/typescript/typeparams/consistent/__snapshots__/jsfmt.spec.js.snap
index 9d867e023..b977e2974 100644
--- a/tests/typescript/typeparams/consistent/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/typescript/typeparams/consistent/__snapshots__/jsfmt.spec.js.snap
@@ -1,5 +1,22 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`flow-only.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript", "flow", "babel-flow", "babel"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+
+const foo6: Fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo<empty> = a;
+const foo7: Fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo<mixed> = a;
+
+=====================================output=====================================
+const foo6: Fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo<empty> = a;
+const foo7: Fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo<mixed> = a;
+
+================================================================================
+`;
+
 exports[`issue-9501.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript", "flow", "babel-flow", "babel"]
diff --git a/tests/typescript/typeparams/consistent/flow-only.ts b/tests/typescript/typeparams/consistent/flow-only.ts
new file mode 100644
index 000000000..c4f7f6e5f
--- /dev/null
+++ b/tests/typescript/typeparams/consistent/flow-only.ts
@@ -0,0 +1,3 @@
+
+const foo6: Fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo<empty> = a;
+const foo7: Fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo<mixed> = a;