[enzyme-adapter-utils] elementToTree: back compat: support naive mapping

Author: ljharb

packages/enzyme-adapter-react-13/src/ReactThirteenElementToTree.js

@@ -23,7 +23,7 @@ export default function elementToTree(el) {
   const { children } = props;
   let rendered = null;
   if (isArrayLike(children)) {
-    rendered = flatten([...children]).map(el => elementToTree(el));
+    rendered = flatten([...children]).map(elementToTree);
   } else if (typeof children !== 'undefined') {
     rendered = elementToTree(children);
   }

packages/enzyme-adapter-utils/src/Utils.js

@@ -181,6 +181,10 @@ export function ensureKeyOrUndefined(key) {
 }
 
 export function elementToTree(el, recurse = elementToTree) {
+  if (typeof recurse !== 'function' && arguments.length === 3) {
+    // special case for backwards compat for `.map(elementToTree)`
+    recurse = elementToTree; // eslint-disable-line no-param-reassign
+  }
   if (el === null || typeof el !== 'object' || !('type' in el)) {
     return el;
   }