Change default behavior to act the same as babel-preset-latest (#33)

* Do not throw on empty options, and default to latest preset

* fix lint

experimental/babel-preset-env/.eslintignore

@@ -0,0 +1 @@
+fixtures

experimental/babel-preset-env/README.md

@@ -18,6 +18,8 @@ This should be straightforward to do in most cases. There might be cases were pl
 
 #### Support all plugins in Babel that are considered `latest`
 
+> Default behavior without options is the same as `babel-preset-latest`.
+
 [#14](https://github.com/babel/babel-preset-env/issues/14) - It won't include `stage-x` plugins. env will support all plugins in what we consider the latest version of Javascript (by matching what we do in [`babel-preset-latest`](http://babeljs.io/docs/plugins/preset-latest/)).
 
 #### Determine the lowest common denominator of plugins to be included in the preset
@@ -55,28 +57,13 @@ Currently: "chrome, edge, firefox, safari, ie, node".
 
 > If your config is a js file, also do `"node": parseFloat(process.versions.node)`
 
-* `loose` (boolean) - Enable "loose" transformations for any plugins in this preset that allow them (Disabled by default).
-* `modules` - Enable transformation of ES6 module syntax to another module type (Enabled by default to `"commonjs"`).
+* `loose` (boolean) - Enable "loose" transformations for any plugins in this preset that allow them (Defaults to `false`).
+* `modules` - Enable transformation of ES6 module syntax to another module type (Defaults to `"commonjs"`).
   * Can be `false` to not transform modules, or one of `["amd", "umd", "systemjs", "commonjs"]`.
-* `debug` (boolean) - `console.log` out the targets and plugins being used as well as the version specified in `/data/plugins.json`.
+* `debug` (boolean) - `console.log` out the targets and plugins being used as well as the version specified in `/data/plugins.json`. (Defaults to `false`)
 * `whitelist` (Array<string>) - Enable a whitelist of plugins to always include. (Defaults to `[]`)
   * Useful if there is a bug in a native implementation, or a combination of a non-supported feature + a supported one doesn't work. (Ex: Node 4 supports native classes but not spread) 
 
-```js
-{
-  "presets": [
-    ["env", {
-      "targets": {
-        "chrome": 52,
-        "browsers": "last 2 safari versions"
-      },
-      "loose": true,
-      "modules": false
-    }]
-  ]
-}
-```
-
 ### Example
 
 ```js
@@ -85,11 +72,9 @@ export class A {}
 ```
 
 ```js
-// default is to run all transforms
+// default is to run all transforms (acts as babel-preset-latest)
 {
-  "presets": [
-    ["env", {}]
-  ]
+  "presets": ["env"]
 }
 
 // ...
@@ -118,14 +103,15 @@ exports.A = A;
 ```
 
 ```js
-// target chrome 52 with webpack 2/rollup
+// target chrome 52 with webpack 2/rollup and loose mode
 {
   "presets": [
     ["env", {
       "targets": {
         "chrome": 52
       },
-      "modules": false
+      "modules": false,
+      "loose": true
     }]
   ]
 }

experimental/babel-preset-env/package.json

@@ -14,9 +14,8 @@
     "lint": "eslint scripts src test",
     "fix": "eslint scripts src test --fix",
     "ci": "npm run test",
-    "prepublish": "npm run build",
     "changelog": "git log `git describe --tags --abbrev=0`..HEAD --pretty=format:' * %s (%an)' | grep -v 'Merge pull request'",
-    "test": "mocha ./test --compilers js:babel-register"
+    "test": "npm run build && mocha ./test --compilers js:babel-register"
   },
   "dependencies": {
     "babel-plugin-check-es2015-constants": "^6.3.13",
@@ -85,6 +84,9 @@
     },
     "rules": {
       "max-len": 0
+    },
+    "env": {
+      "mocha": true
     }
   }
 }

experimental/babel-preset-env/src/index.js

@@ -26,7 +26,7 @@ export const isPluginRequired = (supportedEnvironments, plugin) => {
   if (targetEnvironments.length === 0) { return true; }
 
   const isRequiredForEnvironments = targetEnvironments
-    .filter(environment => {
+    .filter((environment) => {
       // Feature is not implemented in that environment
       if (!plugin[environment]) { return true; }
 
@@ -43,7 +43,7 @@ export const isPluginRequired = (supportedEnvironments, plugin) => {
   return isRequiredForEnvironments.length > 0 ? true : false;
 };
 
-const isBrowsersQueryValid = browsers => {
+const isBrowsersQueryValid = (browsers) => {
   return typeof browsers === "string" || Array.isArray(browsers);
 };
 
@@ -64,7 +64,7 @@ const mergeBrowsers = (fromQuery, fromTarget) => {
   }, fromQuery);
 };
 
-const getTargets = targetOpts => {
+const getTargets = (targetOpts = {}) => {
   const browserOpts = targetOpts.browsers;
   if (isBrowsersQueryValid(browserOpts)) {
     const queryBrowsers = getLowestVersions(browserslist(browserOpts));
@@ -113,23 +113,7 @@ export const validateWhitelistOption = (whitelistOpt = []) => {
   return whitelistOpt;
 };
 
-export default function buildPreset(context, opts) {
-  if (!opts.targets) {
-    throw new Error(
-`
-babel-preset-env requires a "targets" option:
-{
-  "presets": [
-    ["env", {
-      "targets": {
-        "chrome": 50
-      }
-    }]
-  ]
-}
-`);
-  }
-
+export default function buildPreset(context, opts = {}) {
   const loose = validateLooseOption(opts.loose);
   const moduleType = validateModulesOption(opts.modules);
   const whitelist = validateWhitelistOption(opts.whitelist);
@@ -137,7 +121,7 @@ babel-preset-env requires a "targets" option:
   const debug = opts.debug;
 
   let transformations = Object.keys(pluginList)
-    .filter(pluginName => isPluginRequired(targets, pluginList[pluginName]));
+    .filter((pluginName) => isPluginRequired(targets, pluginList[pluginName]));
 
   if (debug) {
     console.log("");
@@ -146,7 +130,7 @@ babel-preset-env requires a "targets" option:
     console.log("Using plugins:");
     console.log("");
     console.log(`module: ${moduleType}`);
-    transformations.forEach(transform => {
+    transformations.forEach((transform) => {
       let envList = pluginList[transform];
       let filteredList = Object.keys(targets)
       .reduce((a, b) => {
@@ -157,7 +141,7 @@ babel-preset-env requires a "targets" option:
     });
   }
 
-  transformations = [...transformations, ...whitelist].map(pluginName => {
+  transformations = [...transformations, ...whitelist].map((pluginName) => {
     return [require(`babel-plugin-${pluginName}`), { loose }];
   });
 

experimental/babel-preset-env/test/fixtures/preset-options/empty-options/actual.js

@@ -0,0 +1 @@
+const a = "1";

experimental/babel-preset-env/test/fixtures/preset-options/empty-options/expected.js

@@ -0,0 +1,3 @@
+"use strict";
+
+var a = "1";

experimental/babel-preset-env/test/fixtures/preset-options/empty-options/options.json

@@ -0,0 +1,5 @@
+{
+  "presets": [
+    ["../../../../lib", {}]
+  ]
+}

experimental/babel-preset-env/test/fixtures/preset-options/modules-false/actual.js

@@ -1 +1 @@
-import a from 'a';
+import a from "a";

experimental/babel-preset-env/test/fixtures/preset-options/modules-false/expected.js

@@ -1 +1 @@
-import a from 'a';
+import a from "a";

experimental/babel-preset-env/test/fixtures/preset-options/modules-false/options.json

@@ -1,7 +1,6 @@
 {
   "presets": [
     ["../../../../lib", {
-      "targets": {},
       "modules": false
     }]
   ]

experimental/babel-preset-env/test/fixtures/preset-options/no-options/actual.js

@@ -0,0 +1 @@
+const a = "1";

experimental/babel-preset-env/test/fixtures/preset-options/no-options/expected.js

@@ -0,0 +1,3 @@
+"use strict";
+
+var a = "1";

experimental/babel-preset-env/test/fixtures/preset-options/no-options/options.json

@@ -0,0 +1,5 @@
+{
+  "presets": [
+    "../../../../lib"
+  ]
+}

experimental/babel-preset-env/test/fixtures/preset-options/whitelist/actual.js

@@ -1 +1 @@
-import a from 'a';
+import a from "a";

experimental/babel-preset-env/test/fixtures/preset-options/whitelist/expected.js

@@ -1,7 +1,7 @@
-'use strict';
+"use strict";
 
-var _a = require('a');
+var _a = require("a");
 
 var _a2 = _interopRequireDefault(_a);
 
-function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }