Merge branch 'master' into docs

Author: jack-lewin

.gitignore

@@ -33,6 +33,8 @@ node_modules
 _book
 
 # Only apps should have lockfiles
+npm-shrinkwrap.json
 package-lock.json
+yarn.lock
 
 packages/*/build/

docs/guides/migration-from-2-to-3.md

@@ -4,18 +4,18 @@ The change from enzyme v2.x to v3.x is a more significant change than in previou
 due to the fact that the internal implementation of enzyme has been almost completely rewritten.
 
 The goal of this rewrite was to address a lot of the major issues that have plagued enzyme since
-its initial release. It was also to simultaneously remove a lot of the dependence that enzyme has
-on react internals, and to make enzyme more "pluggable", paving the way for enzyme to be used
+its initial release. It was also to simultaneously remove a lot of the dependencies that enzyme has
+on React internals, and to make enzyme more "pluggable", paving the way for enzyme to be used
 with "React-like" libraries such as Preact and Inferno.
 
 We have done our best to make enzyme v3 as API compatible with v2.x as possible, however there are
-a hand full of breaking changes that we decided we needed to make, intentionally, in order to
+a handful of breaking changes that we decided we needed to make, intentionally, in order to
 support this new architecture and also improve the usability of the library long-term.
 
 Airbnb has one of the largest enzyme test suites, coming in at around 30,000 enzyme unit tests.
 After upgrading enzyme to v3.x in Airbnb's code base, 99.6% of these tests succeeded with no
 modifications at all. Most of the tests that broke we found to be easy to fix, and some we found to
-actually be depending on what could arguably be considered a bug in v2.x, and the breakage was
+actually depend on what could arguably be considered a bug in v2.x, and the breakage was
 actually desired.
 
 In this guide, we will go over a couple of the most common breakages that we ran into, and how to
@@ -27,13 +27,13 @@ find a breakage that doesn't seem to make sense to you, feel free to file an iss
 
 enzyme now has an "Adapter" system. This means that you now need to install enzyme along with
 another module that provides the Adapter that tells enzyme how to work with your version of React
-(or whatever other react-like library you are using).
+(or whatever other React-like library you are using).
 
 At the time of writing this, enzyme publishes "officially supported" adapters for React 0.13.x,
 0.14.x, 15.x, and 16.x. These adapters are npm packages of the form `enzyme-adapter-react-{{version}}`.
 
 You will want to configure enzyme with the adapter you'd like to use before using enzyme in your
-tests. The way to do this is whith `enzyme.configure(...)`. For example, if your project depends
+tests. The way to do this is with `enzyme.configure(...)`. For example, if your project depends
 on React 16, you would want to configure enzyme this way:
 
 ```js
@@ -83,7 +83,7 @@ import { shallow } from 'enzyme';
 import StatusLabel from './path/to/StatusLabel';
 import Icon from './path/to/Icon';
 
-const wrapper = shallow(<StatusIcon id="success" label="Success" />);
+const wrapper = shallow(<StatusLabel id="success" label="Success" />);
 
 const iconCount = wrapper.find(Icon).length;
 ```
@@ -386,7 +386,7 @@ account for this.
 ## Private properties and methods have been removed
 
 There are several properties that are on an enzyme "wrapper" that were considered to be private and
-were undocumented as a result. Despite being undocumented, people may haev been relying on them. In
+were undocumented as a result. Despite being undocumented, people may have been relying on them. In
 an effort to make making changes less likely to be accidentally breaking in the future, we have
 decided to make these properties properly "private". The following properties will no longer be
 accessible on enzyme `shallow` or `mount` instances:

docs/installation/react-16.md

@@ -41,10 +41,10 @@ ES5:
 <!-- eslint no-var: 0 -->
 ```js
 // setup file
-var Enzyme = require('enzyme');
+var enzyme = require('enzyme');
 var Adapter = require('enzyme-adapter-react-16');
 
-configure({ adapter: new Adapter() });
+enzyme.configure({ adapter: new Adapter() });
 ```
 
 <!-- eslint no-var: 0 -->

packages/enzyme-adapter-react-13/README.md

@@ -0,0 +1 @@
+../../README.md

packages/enzyme-adapter-react-14/README.md

@@ -0,0 +1 @@
+../../README.md

packages/enzyme-adapter-react-15.4/README.md

@@ -0,0 +1 @@
+../../README.md

packages/enzyme-adapter-react-15/README.md

@@ -0,0 +1 @@
+../../README.md

packages/enzyme-adapter-react-16/README.md

@@ -0,0 +1 @@
+../../README.md

packages/enzyme-adapter-react-16/src/ReactSixteenAdapter.js

@@ -19,6 +19,7 @@ import {
   createMountWrapper,
   propsWithKeysAndRef,
 } from 'enzyme-adapter-utils';
+import findCurrentFiberUsingSlowPath from './findCurrentFiberUsingSlowPath';
 
 const HostRoot = 3;
 const ClassComponent = 2;
@@ -63,15 +64,15 @@ function toTree(vnode) {
   // TODO(lmr): I'm not really sure I understand whether or not this is what
   // i should be doing, or if this is a hack for something i'm doing wrong
   // somewhere else. Should talk to sebastian about this perhaps
-  const node = vnode.alternate !== null ? vnode.alternate : vnode;
+  const node = findCurrentFiberUsingSlowPath(vnode);
   switch (node.tag) {
     case HostRoot: // 3
       return toTree(node.child);
     case ClassComponent:
       return {
         nodeType: 'class',
         type: node.type,
-        props: { ...vnode.memoizedProps },
+        props: { ...node.memoizedProps },
         key: node.key,
         ref: node.ref,
         instance: node.stateNode,
@@ -83,7 +84,7 @@ function toTree(vnode) {
       return {
         nodeType: 'function',
         type: node.type,
-        props: { ...vnode.memoizedProps },
+        props: { ...node.memoizedProps },
         key: node.key,
         ref: node.ref,
         instance: null,

packages/enzyme-adapter-react-16/src/findCurrentFiberUsingSlowPath.js

@@ -0,0 +1,104 @@
+// Extracted from https://github.com/facebook/react/blob/7bdf93b17a35a5d8fcf0ceae0bf48ed5e6b16688/src/renderers/shared/fiber/ReactFiberTreeReflection.js#L104-L228
+function findCurrentFiberUsingSlowPath(fiber) {
+  const alternate = fiber.alternate;
+  if (!alternate) {
+    return fiber;
+  }
+  // If we have two possible branches, we'll walk backwards up to the root
+  // to see what path the root points to. On the way we may hit one of the
+  // special cases and we'll deal with them.
+  let a = fiber;
+  let b = alternate;
+  while (true) { // eslint-disable-line
+    const parentA = a.return;
+    const parentB = parentA ? parentA.alternate : null;
+    if (!parentA || !parentB) {
+      // We're at the root.
+      break;
+    }
+
+    // If both copies of the parent fiber point to the same child, we can
+    // assume that the child is current. This happens when we bailout on low
+    // priority: the bailed out fiber's child reuses the current child.
+    if (parentA.child === parentB.child) {
+      let child = parentA.child;
+      while (child) {
+        if (child === a) {
+          // We've determined that A is the current branch.
+          return fiber;
+        }
+        if (child === b) {
+          // We've determined that B is the current branch.
+          return alternate;
+        }
+        child = child.sibling;
+      }
+      // We should never have an alternate for any mounting node. So the only
+      // way this could possibly happen is if this was unmounted, if at all.
+      throw new Error('Unable to find node on an unmounted component.');
+    }
+
+    if (a.return !== b.return) {
+      // The return pointer of A and the return pointer of B point to different
+      // fibers. We assume that return pointers never criss-cross, so A must
+      // belong to the child set of A.return, and B must belong to the child
+      // set of B.return.
+      a = parentA;
+      b = parentB;
+    } else {
+      // The return pointers point to the same fiber. We'll have to use the
+      // default, slow path: scan the child sets of each parent alternate to see
+      // which child belongs to which set.
+      //
+      // Search parent A's child set
+      let didFindChild = false;
+      let child = parentA.child;
+      while (child) {
+        if (child === a) {
+          didFindChild = true;
+          a = parentA;
+          b = parentB;
+          break;
+        }
+        if (child === b) {
+          didFindChild = true;
+          b = parentA;
+          a = parentB;
+          break;
+        }
+        child = child.sibling;
+      }
+      if (!didFindChild) {
+        // Search parent B's child set
+        child = parentB.child;
+        while (child) {
+          if (child === a) {
+            didFindChild = true;
+            a = parentB;
+            b = parentA;
+            break;
+          }
+          if (child === b) {
+            didFindChild = true;
+            b = parentB;
+            a = parentA;
+            break;
+          }
+          child = child.sibling;
+        }
+        if (!didFindChild) {
+          throw new Error('Child was not found in either parent set. This indicates a bug ' +
+            'in React related to the return pointer. Please file an issue.');
+        }
+      }
+    }
+  }
+  if (a.stateNode.current === a) {
+    // We've determined that A is the current branch.
+    return fiber;
+  }
+  // Otherwise B has to be current branch.
+  return alternate;
+}
+
+module.exports = findCurrentFiberUsingSlowPath;