Add codemod for 'React.DOM.div' -> 'React.createElement("div"'

Since we are deprecating the 'React.DOM.*' factories,[1] we want to
provide a codemod so that it's easier for folks to upgrade their code.

This will include an option to use 'React.createFactory' instead of
'React.createElement' in case there is a use case where that is
preferred.

There is one use of `React.DOM.*` that I have seen which is not covered
here - sometimes it has mistakenly been used for Flow typing. In the
cases I have found it is not proper syntax and doesn't seem like
something we should cover with this codemod.

[1]: facebook/react#9398
and facebook/react#8356

transforms/React-DOM-to-react-dom-factories.js

@@ -0,0 +1,190 @@
+/**
+ * Copyright 2013-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+'use strict';
+
+module.exports = function(file, api, options) {
+  const j = api.jscodeshift;
+  const root = j(file.source);
+
+  let hasModifications;
+
+  const DOMModuleName = 'DOM';
+
+  const isDOMSpecifier = specifier => (
+    specifier.imported &&
+    specifier.imported.name === DOMModuleName
+  );
+
+  /**
+   * Replaces 'DOM' with 'createElement' in places where we grab 'DOM' out of
+   * 'React' with destructuring.
+   */
+  const replaceDestructuredDOMStatement = (j, root) => {
+    let hasModifications = false;
+    //---------
+    // First update import statments. eg:
+    // import {
+    //   DOM,
+    //   foo,
+    // } from 'react';
+    root
+      .find(j.ImportDeclaration)
+      .filter(path => (
+        path.node.specifiers.filter(isDOMSpecifier).length > 0 &&
+        path.node.source.value === 'react'
+      ))
+      .forEach(path => {
+        hasModifications = true;
+
+        // Replace the DOM key with 'createElement'
+        path.node.specifiers = path.node.specifiers.map(
+          specifier => {
+            if (specifier.imported && specifier.imported.name === DOMModuleName) {
+              return j.importSpecifier(j.identifier('createElement'));
+            } else {
+              return specifier;
+            }
+          }
+        );
+      });
+
+    //---------
+    // Next update require statments.
+    // This matches both
+    // const {
+    //   Component,
+    //   DOM,
+    // } = React;
+    // and
+    // const {
+    //   Component,
+    //   DOM,
+    // } = require('react');
+    root
+      .find(j.ObjectPattern)
+      .filter(path => (
+        path.parent.node.init &&
+        (
+          // matches '} = React;'
+          path.parent.node.init.name === 'React'
+          ||
+          (
+            // matches "} = require('react');"
+            path.parent.node.init.type === 'CallExpression' &&
+            path.parent.node.init.callee.name === 'require' &&
+            path.parent.node.init.arguments[0].value === 'react'
+          )
+        ) &&
+        path.node.properties.some(property => {
+          return property.key.name === DOMModuleName;
+        })
+      ))
+      .forEach(path => {
+        hasModifications = true;
+
+        // Replace the DOM key with 'createElement'
+        path.node.properties = path.node.properties.map((property) => {
+          if (property.key.name === DOMModuleName) {
+            return j.identifier('createElement');
+          } else {
+            return property;
+          }
+        });
+      });
+    return hasModifications;
+  };
+
+  hasModifications =
+    replaceDestructuredDOMStatement(j, root) || hasModifications;
+
+  const isDOMIdentifier = path => (
+    path.node.name === DOMModuleName &&
+    path.parent.parent.node.type === 'CallExpression'
+  );
+
+  /**
+   * Update cases where DOM.div is being called
+   * eg 'foo = DOM.div('a'...'
+   * replace with 'foo = createElement('div', 'a'...'
+   */
+  function replaceDOMReferences(j, root) {
+    let hasModifications = false;
+
+    root
+      .find(j.Identifier)
+      .filter(isDOMIdentifier)
+      .forEach(path => {
+        hasModifications = true;
+
+        const DOMargs = path.parent.parent.node.arguments;
+        const DOMFactoryPath = path.parent.node.property;
+        const DOMFactoryType = DOMFactoryPath.name;
+
+        // DOM.div(... -> createElement(...
+        j(path.parent).replaceWith(
+          j.identifier('createElement')
+        );
+        // createElement(... -> createElement('div', ...
+        DOMargs.unshift(j.literal(DOMFactoryType));
+      });
+
+    return hasModifications;
+  }
+
+  // We only need to update 'DOM.div' syntax if there was a deconstructed
+  // reference to React.DOM
+  if (hasModifications) {
+    hasModifications = replaceDOMReferences(j, root) || hasModifications;
+  }
+
+  // matches 'React.DOM'
+  const isReactDOMIdentifier = path => (
+    path.node.name === DOMModuleName &&
+    (
+    path.parent.node.type === 'MemberExpression' &&
+    path.parent.node.object.name === 'React'
+    )
+  );
+
+  /**
+   * Update React.DOM references
+   * eg 'foo = React.DOM.div('a'...'
+   * replace with 'foo = React.createElement('div', 'a'...'
+   */
+  function replaceReactDOMReferences(j, root) {
+    let hasModifications = false;
+
+    root
+      .find(j.Identifier)
+      .filter(isReactDOMIdentifier)
+      .forEach(path => {
+        hasModifications = true;
+        const DOMargs = path.parent.parent.parent.node.arguments;
+        const DOMFactoryPath = path.parent.parent.node.property;
+        const DOMFactoryType = DOMFactoryPath.name;
+
+        // React.DOM.div(... -> React.DOM.createElement(...
+        path.parent.parent.node.property = j.identifier('createElement');
+        // React.DOM.createElement(... -> React.createElement(...
+        j(path.parent).replaceWith(j.identifier('React'));
+        // React.createElement(... -> React.createElement('div'...
+        DOMargs.unshift(j.literal(DOMFactoryType));
+      });
+
+    return hasModifications;
+  }
+
+  hasModifications = replaceReactDOMReferences(j, root) || hasModifications;
+
+  return hasModifications
+    ? root.toSource({ quote: 'single' })
+    : null;
+};

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-basic-case.input.js

@@ -0,0 +1,7 @@
+const React = require('react');
+
+class Hello extends React.Component {
+  render() {
+    return React.DOM.div(null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-basic-case.output.js

@@ -0,0 +1,7 @@
+const React = require('react');
+
+class Hello extends React.Component {
+  render() {
+    return React.createElement('div', null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-deconstructed-import.input.js

@@ -0,0 +1,11 @@
+import ReactDOM from 'ReactDOM';
+import {
+  Component,
+  DOM
+} from 'react';
+
+class Hello extends Component {
+  render() {
+    return DOM.div(null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-deconstructed-import.output.js

@@ -0,0 +1,11 @@
+import ReactDOM from 'ReactDOM';
+import {
+  Component,
+  createElement
+} from 'react';
+
+class Hello extends Component {
+  render() {
+    return createElement('div', null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-deconstructed-require-part-two.input.js

@@ -0,0 +1,11 @@
+const ReactDOM = require('ReactDOM');
+const {
+  Component,
+  DOM
+} = require('react');
+
+class Hello extends Component {
+  render() {
+    return DOM.div(null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-deconstructed-require-part-two.output.js

@@ -0,0 +1,11 @@
+const ReactDOM = require('ReactDOM');
+const {
+  Component,
+  createElement
+} = require('react');
+
+class Hello extends Component {
+  render() {
+    return createElement('div', null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-deconstructed-require.input.js

@@ -0,0 +1,12 @@
+const React = require('react');
+const ReactDOM = require('ReactDOM');
+const {
+  Component,
+  DOM
+} = React;
+
+class Hello extends Component {
+  render() {
+    return DOM.div(null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-deconstructed-require.output.js

@@ -0,0 +1,12 @@
+const React = require('react');
+const ReactDOM = require('ReactDOM');
+const {
+  Component,
+  createElement
+} = React;
+
+class Hello extends Component {
+  render() {
+    return createElement('div', null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-no-change-dom-from-other-libraries.input.js

@@ -0,0 +1,13 @@
+let {DOM} = require('Free');
+import {DOM} from 'Free';
+
+const foo = DOM.div('a', 'b', 'c');
+const bar = Free.DOM.div('a', 'b', 'c');
+
+DOM = 'this is a test!';
+
+foo.DOM = {};
+
+foo.DOM.div = () => null;
+
+const bar = foo.DOM.div('a', 'b', 'c');

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-no-change-import.input.js

@@ -0,0 +1,7 @@
+import React from 'react';
+
+class Hello extends React.Component {
+  render() {
+    return React.createElement('div', null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__testfixtures__/React-DOM-to-react-dom-factories/react-dom-no-change-require.input.js

@@ -0,0 +1,7 @@
+const React = require('react');
+
+class Hello extends React.Component {
+  render() {
+    return React.createElement('div', null, `Hello ${this.props.toWhat}`);
+  }
+}

transforms/__tests__/React-DOM-to-react-dom-factories-test.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright 2013-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+'use strict';
+
+const tests = [
+  'react-dom-basic-case',
+  'react-dom-deconstructed-import',
+  'react-dom-deconstructed-require',
+  'react-dom-deconstructed-require-part-two',
+  'react-dom-no-change-import',
+  'react-dom-no-change-require',
+  'react-dom-no-change-dom-from-other-libraries',
+];
+
+const defineTest = require('jscodeshift/dist/testUtils').defineTest;
+
+describe('React-DOM-to-react-dom-factories', () => {
+  tests.forEach(test =>
+    defineTest(
+      __dirname,
+      'React-DOM-to-react-dom-factories',
+      null,
+      `React-DOM-to-react-dom-factories/${ test }`
+    )
+  );
+});