Review feedback

Author: ljharb

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

@@ -23,7 +23,7 @@ export default function elementToTree(el) {
   let rendered = null;
   if (Array.isArray(children)) {
     rendered = flatten(children, true).map(elementToTree);
-  } else if (children !== undefined) {
+  } else if (typeof children !== 'undefined') {
     rendered = elementToTree(children);
   }
   return {

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

@@ -104,7 +104,7 @@ export function elementToTree(el) {
   let rendered = null;
   if (Array.isArray(children)) {
     rendered = flatten(children, true).map(elementToTree);
-  } else if (children !== undefined) {
+  } else if (typeof children !== 'undefined') {
     rendered = elementToTree(children);
   }
   return {

packages/enzyme/src/RSTTraversal.js

@@ -40,11 +40,11 @@ export function treeFilter(tree, fn) {
  * To support sibling selectors we need to be able to find
  * the siblings of a node. The easiest way to do that is find
  * the parent of the node and access its children.
- * 
+ *
  * This would be unneeded if the RST spec included sibling pointers
  * such as node.nextSibling and node.prevSibling
- * @param {*} root 
- * @param {*} targetNode 
+ * @param {*} root
+ * @param {*} targetNode
  */
 export function findParentNode(root, targetNode) {
   const results = treeFilter(
@@ -113,7 +113,7 @@ export function nodeMatchesObjectProps(node, props) {
 }
 
 export function getTextFromNode(node) {
-  if (node === null || node === undefined) {
+  if (node == null) {
     return '';
   }
 

packages/enzyme/src/ReactWrapper.js

@@ -611,7 +611,7 @@ class ReactWrapper {
       throw new Error('ReactWrapper::state() can only be called on the root');
     }
     const _state = this.single('state', () => this.instance().state);
-    if (name !== undefined) {
+    if (typeof name !== 'undefined') {
       return _state[name];
     }
     return _state;
@@ -635,7 +635,7 @@ class ReactWrapper {
       throw new Error('ReactWrapper::context() can only be called on components with instances');
     }
     const _context = instance.context;
-    if (name !== undefined) {
+    if (typeof name !== 'undefined') {
       return _context[name];
     }
     return _context;

packages/enzyme/src/ShallowWrapper.js

@@ -699,7 +699,7 @@ class ShallowWrapper {
       throw new Error('ShallowWrapper::state() can only be called on class components');
     }
     const _state = this.single('state', () => this.instance().state);
-    if (name !== undefined) {
+    if (typeof name !== 'undefined') {
       return _state[name];
     }
     return _state;

packages/enzyme/src/Utils.js

@@ -25,7 +25,7 @@ export function isCustomComponentElement(inst, adapter) {
 function propsOfNode(node) {
   return entries((node && node.props) || {})
     .filter(([, value]) => typeof value !== 'undefined')
-    .reduce((acc, [key, value]) => ({ ...acc, [key]: value }), {});
+    .reduce((acc, [key, value]) => Object.assign(acc, { [key]: value }), {});
 }
 
 export function typeOfNode(node) {
@@ -141,7 +141,7 @@ function childrenToArray(children) {
   const result = [];
 
   const push = (el) => {
-    if (el === null || el === false || el === undefined) return;
+    if (el === null || el === false || typeof el === 'undefined') return;
     result.push(el);
   };
 
@@ -161,7 +161,7 @@ export function childrenToSimplifiedArray(nodeChildren) {
     const child = childrenArray[i];
     const previousChild = simplifiedArray.pop();
 
-    if (previousChild === undefined) {
+    if (typeof previousChild === 'undefined') {
       simplifiedArray.push(child);
     } else if (isTextualNode(child) && isTextualNode(previousChild)) {
       simplifiedArray.push(previousChild + child);
@@ -220,11 +220,11 @@ export function nodeHasProperty(node, propKey, propValue) {
   }
   const nodePropValue = nodeProps[propKey];
 
-  if (nodePropValue === undefined) {
+  if (typeof nodePropValue === 'undefined') {
     return false;
   }
 
-  if (propValue !== undefined) {
+  if (typeof propValue !== 'undefined') {
     return is(nodePropValue, propValue);
   }
 

packages/enzyme/src/selectors.js

@@ -142,7 +142,7 @@ export function buildPredicate(selector) {
   // If the selector is an non-empty object, treat the keys/values as props
   if (typeof selector === 'object') {
     if (!Array.isArray(selector) && selector !== null && !isEmpty(selector)) {
-      const hasUndefinedValues = values(selector).some(value => value === undefined);
+      const hasUndefinedValues = values(selector).some(value => typeof value === 'undefined');
       if (hasUndefinedValues) {
         throw new TypeError('Enzyme::Props can’t have `undefined` values. Try using ‘findWhere()’ instead.');
       }