Adds support for more React imports and fixes a bunch of bugs

Author: trueadm

packages/babel-plugin-optimize-react/.gitignore

@@ -0,0 +1 @@
+sandbox.js

packages/babel-plugin-optimize-react/__tests__/__snapshots__/createElement-test.js.snap

@@ -21,6 +21,17 @@ export function MyComponent() {
 }"
 `;
 
+exports[`React createElement transforms should transform React.createElement calls #4 1`] = `
+"import * as React from \\"react\\";
+const __reactCreateElement__ = React.createElement;
+
+const node = __reactCreateElement__(\\"div\\", null, __reactCreateElement__(\\"span\\", null, \\"Hello world!\\"));
+
+export function MyComponent() {
+  return node;
+}"
+`;
+
 exports[`React createElement transforms should transform React.createElement calls 1`] = `
 "import React from \\"react\\";
 const __reactCreateElement__ = React.createElement;

packages/babel-plugin-optimize-react/__tests__/__snapshots__/hooks-test.js.snap

@@ -109,18 +109,32 @@ const {
 
 exports[`React hook transforms should support mixed hook imports 1`] = `
 "import React from \\"react\\";
-import { memo } from \\"react\\";
+import \\"react\\";
 const {
+  memo,
   useState
 } = React;"
 `;
 
+exports[`React hook transforms should support mixed hook imports with no default #2 1`] = `
+"import React from \\"react\\";
+const {
+  memo,
+  useRef,
+  useState
+} = React;
+export const Portal = memo(() => null);"
+`;
+
 exports[`React hook transforms should support mixed hook imports with no default 1`] = `
 "import React from \\"react\\";
 const {
   useState
 } = React;
-import { memo } from \\"react\\";"
+import \\"react\\";
+const {
+  memo
+} = React;"
 `;
 
 exports[`React hook transforms should support transform hook imports 1`] = `

packages/babel-plugin-optimize-react/__tests__/createElement-test.js

@@ -47,4 +47,18 @@ describe('React createElement transforms', () => {
     const output = transform(test);
     expect(output).toMatchSnapshot();
   });
+
+  it('should transform React.createElement calls #4', () => {
+    const test = `
+      import * as React from "react";
+  
+      const node = React.createElement("div", null, React.createElement("span", null, "Hello world!"));
+  
+      export function MyComponent() {
+        return node;
+      }
+    `;
+    const output = transform(test);
+    expect(output).toMatchSnapshot();
+  });
 });

packages/babel-plugin-optimize-react/__tests__/hooks-test.js

@@ -147,4 +147,14 @@ describe('React hook transforms', () => {
     const output = transform(test);
     expect(output).toMatchSnapshot();
   });
+
+  it('should support mixed hook imports with no default #2', () => {
+    const test = `
+      import {memo, useRef, useState} from "react";
+
+      export const Portal = memo(() => null);
+    `;
+    const output = transform(test);
+    expect(output).toMatchSnapshot();
+  });
 });

packages/babel-plugin-optimize-react/index.js

@@ -13,17 +13,47 @@ const reactHooks = new Set([
   'useState',
 ]);
 
+const reactNamedImports = new Set([
+  'Children',
+  'cloneElement',
+  'Component',
+  'ConcurrentMode',
+  'createContext',
+  'createElement',
+  'createFactory',
+  'forwardRef',
+  'Fragment',
+  'isValidElement',
+  'lazy',
+  'memo',
+  'Profiler',
+  'PureComponent',
+  'StrictMode',
+  'Suspense',
+  'useCallback',
+  'useContext',
+  'useDebugValue',
+  'useEffect',
+  'useImperativeHandle',
+  'useLayoutEffect',
+  'useMemo',
+  'useReducer',
+  'useRef',
+  'useState',
+  'version',
+]);
+
 module.exports = function(babel) {
   const { types: t } = babel;
 
-  // Collects named imports of React hooks from the "react" package
-  function collectReactHooksAndRemoveTheirNamedImports(path, state) {
+  // Collects named imports from the "react" package
+  function collectAllReactImportalsAndRemoveTheirNamedImports(path, state) {
     const node = path.node;
     const hooks = [];
     if (t.isStringLiteral(node.source) && node.source.value === 'react') {
       const specifiers = path.get('specifiers');
-      if (state.hasDefaultSpecifier === undefined) {
-        state.hasDefaultSpecifier = false;
+      if (state.hasDefaultOrNamespaceSpecifier === undefined) {
+        state.hasDefaultOrNamespaceSpecifier = false;
       }
 
       for (let specifier of specifiers) {
@@ -32,7 +62,7 @@ module.exports = function(babel) {
           const localNode = specifier.node.local;
 
           if (t.isIdentifier(importedNode) && t.isIdentifier(localNode)) {
-            if (reactHooks.has(importedNode.name)) {
+            if (reactNamedImports.has(importedNode.name)) {
               hooks.push({
                 imported: importedNode.name,
                 local: localNode.name,
@@ -41,17 +71,33 @@ module.exports = function(babel) {
             }
           }
         } else if (t.isImportDefaultSpecifier(specifier)) {
-          state.hasDefaultSpecifier = true;
+          const local = specifier.get('local');
+
+          if (t.isIdentifier(local) && local.node.name === 'React') {
+            state.hasDefaultOrNamespaceSpecifier = true;
+          }
+        } else if (t.isImportNamespaceSpecifier(specifier)) {
+          const local = specifier.get('local');
+
+          if (t.isIdentifier(local) && local.node.name === 'React') {
+            state.hasDefaultOrNamespaceSpecifier = true;
+          }
         }
       }
       // If there is no default specifier for React, add one
-      if (state.hasDefaultSpecifier === false && specifiers.length > 0) {
+      if (
+        state.hasDefaultOrNamespaceSpecifier === false &&
+        specifiers.length > 0
+      ) {
         const defaultSpecifierNode = t.importDefaultSpecifier(
           t.identifier('React')
         );
 
-        path.pushContainer('specifiers', defaultSpecifierNode);
-        state.hasDefaultSpecifier = true;
+        // We unshift so it goes to the beginning
+        path.unshiftContainer('specifiers', defaultSpecifierNode);
+        state.hasDefaultOrNamespaceSpecifier = true;
+        // Make sure we register the binding, so tracking continues to work
+        path.scope.registerDeclaration(path);
       }
     }
     return hooks;
@@ -65,7 +111,10 @@ module.exports = function(babel) {
       if (binding !== undefined) {
         const bindingPath = binding.path;
 
-        if (t.isImportDefaultSpecifier(bindingPath)) {
+        if (
+          t.isImportDefaultSpecifier(bindingPath) ||
+          t.isImportNamespaceSpecifier(bindingPath)
+        ) {
           const parentPath = bindingPath.parentPath;
 
           if (
@@ -187,6 +236,7 @@ module.exports = function(babel) {
 
     if (
       t.isImportDefaultSpecifier(bindingPath) ||
+      t.isImportNamespaceSpecifier(bindingPath) ||
       t.isVariableDeclarator(bindingPath)
     ) {
       bindingPath.parentPath.insertAfter(createElementDeclaration);
@@ -205,18 +255,18 @@ module.exports = function(babel) {
         //   import React, {useState} from "react";
         // As we collection them, we also remove the imports from the declaration.
 
-        const importedHooks = collectReactHooksAndRemoveTheirNamedImports(
+        const reactNamedImports = collectAllReactImportalsAndRemoveTheirNamedImports(
           path,
           state
         );
-        if (importedHooks.length > 0) {
+        if (reactNamedImports.length > 0) {
           // Create a destructured variable declaration. i.e.:
-          //   const {useEffect, useState} = React;
+          //   const {memo, useEffect, useState} = React;
           // Then insert it below the import declaration node.
 
           const declarations = t.variableDeclarator(
             t.objectPattern(
-              importedHooks.map(({ imported, local }) =>
+              reactNamedImports.map(({ imported, local }) =>
                 t.objectProperty(
                   t.identifier(imported),
                   t.identifier(local),

packages/babel-plugin-optimize-react/package.json

@@ -1,6 +1,6 @@
 {
   "name": "babel-plugin-optimize-react",
-  "version": "0.0.3",
+  "version": "0.0.4",
   "description": "Babel plugin for optimizing common React patterns",
   "repository": "facebookincubator/create-react-app",
   "license": "MIT",