handle deep mounted memo components properly

src/mount.js

@@ -1,6 +1,6 @@
 import omitBy from 'lodash/omitBy';
 import isNil from 'lodash/isNil';
-import {ForwardRef} from 'react-is';
+import {ForwardRef, Memo} from 'react-is';
 
 import {typeName} from 'enzyme/build/Debug';
 import {childrenOfNode, propsOfNode} from 'enzyme/build/RSTTraversal';
@@ -46,12 +46,19 @@ function internalNodeToJson(node, options) {
   }
 
   if (Array.isArray(node)) {
+    // enzyme does some funny stuff with memo function components turning the children
+    // into an array resulting in undesirable snapshots
+    if (node.length === 1) {
+      return internalNodeToJson(node[0], options);
+    }
     return node.map(child => internalNodeToJson(child, options));
   }
 
   if (
     options.mode === 'deep' &&
-    (typeof node.type === 'function' || node.type.$$typeof === ForwardRef)
+    (typeof node.type === 'function' ||
+      node.type.$$typeof === ForwardRef ||
+      node.type.$$typeof === Memo)
   ) {
     return internalNodeToJson(node.rendered, options);
   }

tests/__snapshots__/mount-deep.test.js.snap

@@ -244,6 +244,45 @@ exports[`excludes forwardRef node but renders wrapped component 1`] = `
 </div>
 `;
 
+exports[`excludes memo node but renders wrapped component 1`] = `
+<div
+  className="basic-memo foo"
+  onClick={[Function]}
+>
+  <div
+    className="group"
+    id="group-id"
+  >
+    <span
+      className="empty"
+    />
+  </div>
+</div>
+`;
+
+exports[`excludes memo node but renders wrapped top level array properly 1`] = `
+Array [
+  <div
+    className="test"
+    key="test"
+  >
+    Test
+  </div>,
+  <div
+    className="test2"
+    key="test2"
+  >
+    Test 2
+  </div>,
+  <div
+    className="foo"
+    key="test3"
+  >
+    Test 3
+  </div>,
+]
+`;
+
 exports[`handles a component which returns null 1`] = `""`;
 
 exports[`includes undefined props 1`] = `

tests/fixtures/memo.js

@@ -0,0 +1,32 @@
+import React from 'react';
+
+function BasicComponent(props) {
+  return (
+    <div
+      className={`basic-memo ${props.className}`}
+      onClick={function handleOnClick() {}}
+    >
+      <div id="group-id" className="group">
+        <span className="empty" />
+      </div>
+    </div>
+  );
+}
+
+export const BasicMemo = React.memo(BasicComponent);
+
+function ArrayRender(props) {
+  return [
+    <div className="test" key="test">
+      Test
+    </div>,
+    <div className="test2" key="test2">
+      Test 2
+    </div>,
+    <div className={props.className} key="test3">
+      Test 3
+    </div>,
+  ];
+}
+
+export const ArrayMemo = React.memo(ArrayRender);

tests/mount-deep.test.js

@@ -20,6 +20,7 @@ import {
   ClassArrayRender,
 } from './fixtures/class';
 import {ForwardRefWithDefaultProps} from './fixtures/forwardRef';
+import {BasicMemo, ArrayMemo} from './fixtures/memo';
 
 Enzyme.configure({adapter: new Adapter()});
 const deepOptions = {mode: 'deep'};
@@ -135,3 +136,15 @@ it('excludes forwardRef node but renders wrapped component', () => {
 
   expect(mountToJson(mounted, deepOptions)).toMatchSnapshot();
 });
+
+it.only('excludes memo node but renders wrapped component', () => {
+  const mounted = mount(<BasicMemo className="foo" />);
+
+  expect(mountToJson(mounted, deepOptions)).toMatchSnapshot();
+});
+
+it.only('excludes memo node but renders wrapped top level array properly', () => {
+  const mounted = mount(<ArrayMemo className="foo" />);
+
+  expect(mountToJson(mounted, deepOptions)).toMatchSnapshot();
+});