Adds option for running plugin through babel-preset-env pipeline

README.md

@@ -32,18 +32,29 @@ For more detailed options, run `codemod --help`.
 
 There are [many, many existing plugins](https://yarnpkg.com/en/packages?q=babel-plugin) that you can use. However, if you need to write your own you should consult the [babel handbook](https://github.com/thejameskyle/babel-handbook). If you publish a plugin intended specifically as a codemod, consider using both the [`babel-plugin`](https://yarnpkg.com/en/packages?q=babel-plugin) and [`babel-codemod`](https://yarnpkg.com/en/packages?q=babel-codemod) keywords.
 
-While testing out your plugin, you may find it useful to use the `--require` option when running `codemod` if your plugin is written using JavaScript syntax not supported by the current version of node. For example:
+### Transpiling using babel plugins
+
+`babel-codemod` also supports non-standard/future language features that are not currently supported by the latest version of node.  It does this by leveraging `babel-preset-env` which loads the [latest babel plugins](https://github.com/babel/babel/tree/master/packages/babel-preset-env#support-all-plugins-in-babel-that-are-considered-latest).  This feature is on by default.
+
+This feature should support most use cases when writing plugins in advanced JavaScript syntax. However, if you are writing plugins with syntax that is beyond "latest", or you would like to use your own set of plugins and presets, you can pass in the `--find-babel-config` switch in combination with a local `.babelrc` file that lists the presets/plugins you want applied to your plugin code.
 
 ```
-# Run a local plugin written with newer JavaScript syntax.
-$ codemod --require babel-register --plugin ./my-plugin.js src/
+# Run a local plugin that is passed through locally installed babel plugins
+$ codemod --find-babel-config --plugin ./my-plugin.js src/
+```
+
+This requires that all babel plugins and presets be installed locally and are listed in your `.babelrc` file.  `babel-codemod` uses `babel-register` under the hood too accomplish this and all `.babelrc` [lookup rules apply](https://babeljs.io/docs/usage/babelrc/#lookup-behavior).
 
+### Transpiling using TypeScript
+There is currently an [open issue](https://github.com/square/babel-codemod/issues/51) for supporting plugins written in typescript.  In the interim, you can take the same approach using `--require` along with `ts-node/register`. 
+
+For example:
+
+```
 # Run a local plugin written with TypeScript.
 $ codemod --require ts-node/register --plugin ./my-plugin.ts src/
 ```
 
-Note: You'll need to [setup `babel-register`](https://github.com/square/babel-codemod/pull/25#issuecomment-309607661) if you're using `--require`.
-
 ## Contributing
 
 See [CONTRIBUTING.md](./CONTRIBUTING.md) for information on setting up the project for development and on contributing to the project.

package.json

@@ -43,11 +43,13 @@
     "typescript": "^2.2.1"
   },
   "dependencies": {
-    "babel-core": "^6.23.1",
-    "glob": "^7.1.1",
-    "mz": "^2.6.0",
+    "babel-core": "^6.26.0",
+    "babel-preset-env": "^1.6.1",
+    "babel-register": "^6.26.0",
+    "glob": "^7.1.2",
+    "mz": "^2.7.0",
     "recast": "^0.13.0",
-    "resolve": "^1.3.2"
+    "resolve": "^1.5.0"
   },
   "engines": {
     "node": ">=6.0.0"

src/Options.ts

@@ -16,6 +16,7 @@ export class Plugin {
     readonly rawPlugin: RawBabelPlugin,
     readonly inferredName: string,
     readonly path?: string,
+    readonly resolvedPath?: string,
   ) {
     let instance = rawPlugin(Babel);
 
@@ -25,6 +26,7 @@ export class Plugin {
   }
 
   static load(path: string, inferredName: string) {
+    let resolvedPath = require.resolve(path);
     let exports = require(path);
     let plugin;
 
@@ -39,7 +41,8 @@ export class Plugin {
     return new Plugin(
       rawPlugin,
       inferredName,
-      path
+      path,
+      resolvedPath
     );
   }
 }
@@ -67,14 +70,21 @@ export default class Options {
     readonly pluginOptions: Map<string, object>,
     readonly extensions: Set<string>,
     readonly requires: Array<string>,
+    readonly transpilePlugins: boolean,
+    readonly findBabelConfig: boolean,
     readonly ignore: PathPredicate,
     readonly stdio: boolean,
     readonly help: boolean,
     readonly dry: boolean
   ) {}
 
+  private _pluginCache?: Array<Plugin>;
+
   getPlugins(): Array<Plugin> {
-    return this.plugins.map(plugin => plugin.load());
+    if (!this._pluginCache) {
+      this._pluginCache = this.plugins.map(plugin => plugin.load());
+    }
+    return this._pluginCache;
   }
 
   loadRequires() {
@@ -83,6 +93,16 @@ export default class Options {
     }
   }
 
+  loadBabelTranspile() {
+    let pluginOptions;
+    if (!this.findBabelConfig) {
+      pluginOptions = require('babel-preset-env').default();
+      pluginOptions.babelrc = false; // ignore babelrc file if present
+    }
+
+    require('babel-register')(pluginOptions);
+  }
+
   getPlugin(name: string): Plugin | null {
     for (let plugin of this.getPlugins()) {
       if (plugin.declaredName === name || plugin.inferredName === name) {
@@ -134,6 +154,8 @@ export default class Options {
     let extensions = DEFAULT_EXTENSIONS;
     let ignore = (path: string, basename: string, root: string) => basename[0] === '.';
     let requires: Array<string> = [];
+    let findBabelConfig = false;
+    let transpilePlugins = true;
     let stdio = false;
     let help = false;
     let dry = false;
@@ -177,6 +199,16 @@ export default class Options {
           requires.push(getRequirableModulePath(args[i]));
           break;
 
+        case '--transpile-plugins':
+        case '--no-transpile-plugins':
+          transpilePlugins = arg === '--transpile-plugins';
+          break;
+
+        case '--find-babel-config':
+        case '--no-find-babel-config':
+          findBabelConfig = arg === '--find-babel-config';
+          break;
+
         case '--extensions':
           i++;
           extensions = new Set(
@@ -221,6 +253,8 @@ export default class Options {
       pluginOptions,
       extensions,
       requires,
+      transpilePlugins,
+      findBabelConfig,
       ignore,
       stdio,
       help,

src/index.ts

@@ -15,6 +15,9 @@ OPTIONS
   -o, --plugin-options PLUGIN=OPTS  JSON-encoded OPTS for PLUGIN (allows multiple).
   -r, --require PATH                Require PATH before transform (allows multiple).
       --extensions EXTS             Comma-separated extensions to process (default: "${Array.from(DEFAULT_EXTENSIONS).join(',')}").
+      --[no-]transpile-plugins      Transpile plugins to enable future syntax (default: on).
+      --[no-]find-babel-config      Run plugins through babel plugins/presets specified in local
+                                    .babelrc file instead of babel-preset-env (default: off).
   -s, --stdio                       Read source from stdin and print to stdout.
   -h, --help                        Show this help message.
   -d, --dry                         Run plugins without modifying files on disk.
@@ -39,9 +42,6 @@ EXAMPLES
   # Pass options from a config file to a plugin.
   $ ${$0} -p ./a.js -o [email protected] src/
 
-  # Run with a plugin which itself is transpiled using babel.
-  $ ${$0} -r babel-register -p ./some-plugin.js src/
-
   # Run with a plugin written in TypeScript.
   $ ${$0} -r ts-node/register -p ./some-plugin.ts src/
   `.trim());
@@ -68,6 +68,8 @@ export default async function run(
     return 0;
   }
 
+  options.loadBabelTranspile();
+
   options.loadRequires();
 
   let plugins = options.getBabelPlugins();

test/CLITest.ts

@@ -187,4 +187,53 @@ describe('CLI', function() {
       '3 + 4;'
     );
   });
+
+  it('can load plugins written with ES modules by default', async function() {
+    let afile = await createTemporaryFile('a-file.js', '3 + 4;');
+    let { status, stdout, stderr } = await runCodemodCLI([afile, '-p', plugin('increment-export-default')]);
+
+    deepEqual(
+      { status, stdout, stderr },
+      {
+        status: 0,
+        stdout: `${afile}\n1 file(s), 1 modified, 0 errors\n`,
+        stderr: ''
+      }
+    );
+    strictEqual(
+      await readFile(afile, 'utf8'),
+      '4 + 5;'
+    );
+  });
+
+  it('can load plugins with multiple files with ES modules by default`', async function() {
+    let afile = await createTemporaryFile('a-file.js', '3 + 4;');
+    let pluginFile = join(__dirname, `fixtures/plugin/increment-export-default-multiple/increment-export-default.js`);
+    let { status, stdout, stderr } = await runCodemodCLI([afile, '-p', pluginFile]);
+
+    deepEqual(
+      { status, stdout, stderr },
+      {
+        status: 0,
+        stdout: `${afile}\n1 file(s), 1 modified, 0 errors\n`,
+        stderr: ''
+      }
+    );
+    strictEqual(
+      await readFile(afile, 'utf8'),
+      '4 + 5;'
+    );
+  });
+
+  it('fails when specifying --find-babel-config as there are no plugins loaded', async function() {
+    let afile = await createTemporaryFile('a-file.js', '3 + 4;');
+    let { status, stdout, stderr } = await runCodemodCLI([afile, '-p', plugin('increment-export-default'), '--find-babel-config']);
+
+    ok(
+      /SyntaxError: Unexpected token export/.test(stderr),
+      `error should reference invalid syntax: ${stderr}`
+    );
+    strictEqual(stdout, '');
+    strictEqual(status, 255);
+  });
 });

test/OptionsTest.ts

@@ -100,6 +100,11 @@ describe('Options', function() {
     strictEqual(options.dry, true);
   });
 
+  it('should set useLocalBabel', function() {
+    let options = assertOptionsParsed(Options.parse(['--find-babel-config']));
+    strictEqual(options.findBabelConfig, true);
+  });
+
   function assertOptionsParsed(result: ParseOptionsResult): Options {
     if (result instanceof Options) {
       return result;

test/fixtures/plugin/increment-export-default-multiple/increment-export-default.js

@@ -0,0 +1,11 @@
+import incrementValue from './increment-value'
+
+export default function() {
+  return {
+    visitor: {
+      NumericLiteral(path) {
+        path.node.value = incrementValue(path.node.value);
+      }
+    }
+  }
+};

test/fixtures/plugin/increment-export-default-multiple/increment-value.js

@@ -0,0 +1,5 @@
+import path from 'path'
+
+export default function incrementValue(value) {
+    return value + 1
+}

test/fixtures/plugin/increment-export-default.js

@@ -0,0 +1,9 @@
+export default function() {
+  return {
+    visitor: {
+      NumericLiteral(path) {
+        path.node.value += 1;
+      }
+    }
+  }
+};