Add uglify as a target (#178)

experimental/babel-preset-env/README.md

@@ -122,6 +122,14 @@ A query to select browsers (ex: last 2 versions, > 5%) using [browserslist](http
 
 Note, browsers' results are overridden by explicit items from `targets`.
 
+### `targets.uglify`
+
+`number | true`
+
+If you are using UglifyJS to minify your code, then targeting later browsers will throw a syntax error.
+
+To prevent this - specify the uglify option, which will enable all plugins and, as a result, fully compile your code to ES5. Note, that useBuiltIns will work as before, and only include the polyfills that your target(s) need.
+
 ### `loose`
 
 `boolean`, defaults to `false`.

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

@@ -94,29 +94,33 @@ const _extends = Object.assign || function (target) {
 
 
 export const getTargets = (targets = {}) => {
-  const targetOps = _extends({}, targets);
+  const targetOpts = _extends({}, targets);
 
-  if (targetOps.node === true || targetOps.node === "current") {
-    targetOps.node = getCurrentNodeVersion();
+  if (targetOpts.node === true || targetOpts.node === "current") {
+    targetOpts.node = getCurrentNodeVersion();
+  }
+
+  if (targetOpts.hasOwnProperty("uglify") && !targetOpts.uglify) {
+    delete targetOpts.uglify;
   }
 
   // Replace Electron target with its Chrome equivalent
-  if (targetOps.electron) {
-    const electronChromeVersion = getElectronChromeVersion(targetOps.electron);
+  if (targetOpts.electron) {
+    const electronChromeVersion = getElectronChromeVersion(targetOpts.electron);
 
-    targetOps.chrome = targetOps.chrome
-      ? Math.min(targetOps.chrome, electronChromeVersion)
+    targetOpts.chrome = targetOpts.chrome
+      ? Math.min(targetOpts.chrome, electronChromeVersion)
       : electronChromeVersion;
 
-    delete targetOps.electron;
+    delete targetOpts.electron;
   }
 
-  const browserOpts = targetOps.browsers;
+  const browserOpts = targetOpts.browsers;
   if (isBrowsersQueryValid(browserOpts)) {
     const queryBrowsers = getLowestVersions(browserslist(browserOpts));
-    return mergeBrowsers(queryBrowsers, targetOps);
+    return mergeBrowsers(queryBrowsers, targetOpts);
   }
-  return targetOps;
+  return targetOpts;
 };
 
 let hasBeenLogged = false;
@@ -143,6 +147,14 @@ const filterItem = (targets, exclusions, list, item) => {
   return isRequired && notExcluded;
 };
 
+const getBuiltInTargets = (targets) => {
+  const builtInTargets = _extends({}, targets);
+  if (builtInTargets.uglify != null) {
+    delete builtInTargets.uglify;
+  }
+  return builtInTargets;
+};
+
 export const transformIncludesAndExcludes = (opts) => ({
   all: opts,
   plugins: opts.filter((opt) => !opt.match(/^(es\d+|web)\./)),
@@ -157,15 +169,17 @@ export default function buildPreset(context, opts = {}) {
   const include = transformIncludesAndExcludes(validatedOptions.include);
   const exclude = transformIncludesAndExcludes(validatedOptions.exclude);
 
+
   const filterPlugins = filterItem.bind(null, targets, exclude.plugins, pluginList);
   const transformations = Object.keys(pluginList)
     .filter(filterPlugins)
     .concat(include.plugins);
 
   let polyfills;
+  let polyfillTargets;
   if (useBuiltIns) {
-    const filterBuiltIns = filterItem.bind(null, targets, exclude.builtIns, builtInsList);
-
+    polyfillTargets = getBuiltInTargets(targets);
+    const filterBuiltIns = filterItem.bind(null, polyfillTargets, exclude.builtIns, builtInsList);
     polyfills = Object.keys(builtInsList)
       .concat(defaultInclude)
       .filter(filterBuiltIns)
@@ -185,7 +199,7 @@ export default function buildPreset(context, opts = {}) {
     if (useBuiltIns && polyfills.length) {
       console.log("\nUsing polyfills:");
       polyfills.forEach((polyfill) => {
-        logPlugin(polyfill, targets, builtInsList);
+        logPlugin(polyfill, polyfillTargets, builtInsList);
       });
     }
   }

experimental/babel-preset-env/test/debug-fixtures/builtins-uglify/options.json

@@ -0,0 +1,13 @@
+{
+  "presets": [
+    ["../../lib", {
+      "debug": true,
+      "targets": {
+        "chrome": 55,
+        "uglify": true
+      },
+      "useBuiltIns": true,
+      "modules": false
+    }]
+  ]
+}

experimental/babel-preset-env/test/debug-fixtures/builtins-uglify/stdout.txt

@@ -0,0 +1,41 @@
+babel-preset-env: `DEBUG` option
+
+Using targets:
+{
+  "chrome": 55,
+  "uglify": true
+}
+
+Modules transform: false
+
+Using plugins:
+  transform-es2015-arrow-functions {"uglify":true}
+  transform-es2015-block-scoped-functions {"uglify":true}
+  transform-es2015-block-scoping {"uglify":true}
+  transform-es2015-classes {"uglify":true}
+  transform-es2015-computed-properties {"uglify":true}
+  check-es2015-constants {"uglify":true}
+  transform-es2015-destructuring {"uglify":true}
+  transform-es2015-for-of {"uglify":true}
+  transform-es2015-function-name {"uglify":true}
+  transform-es2015-literals {"uglify":true}
+  transform-es2015-object-super {"uglify":true}
+  transform-es2015-parameters {"uglify":true}
+  transform-es2015-shorthand-properties {"uglify":true}
+  transform-es2015-spread {"uglify":true}
+  transform-es2015-sticky-regex {"uglify":true}
+  transform-es2015-template-literals {"uglify":true}
+  transform-es2015-typeof-symbol {"uglify":true}
+  transform-es2015-unicode-regex {"uglify":true}
+  transform-regenerator {"uglify":true}
+  transform-exponentiation-operator {"uglify":true}
+  transform-async-to-generator {"uglify":true}
+  syntax-trailing-function-commas {"chrome":55,"uglify":true}
+
+Using polyfills:
+  es7.string.pad-start {"chrome":55}
+  es7.string.pad-end {"chrome":55}
+  web.timers {"chrome":55}
+  web.immediate {"chrome":55}
+  web.dom.iterable {"chrome":55}
+src/in.js -> lib/in.js

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

@@ -0,0 +1,3 @@
+import "babel-polyfill";
+
+const a = 1;

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

@@ -0,0 +1,9 @@
+import "core-js/modules/es7.string.pad-start";
+import "core-js/modules/es7.string.pad-end";
+import "core-js/modules/web.timers";
+import "core-js/modules/web.immediate";
+import "core-js/modules/web.dom.iterable";
+import "regenerator-runtime/runtime";
+
+
+var a = 1;

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

@@ -0,0 +1,12 @@
+{
+  "presets": [
+    ["../../../../lib", {
+      "targets": {
+        "chrome": 55,
+        "uglify": true
+      },
+      "modules": false,
+      "useBuiltIns": true
+    }]
+  ]
+}

experimental/babel-preset-env/test/index.spec.js

@@ -85,6 +85,28 @@ describe("babel-preset-env", () => {
     });
   });
 
+  describe("getTargets + uglify", () => {
+    it("should work with `true`", function() {
+      assert.deepEqual(babelPresetEnv.getTargets({
+        uglify: true
+      }), {
+        uglify: true
+      });
+    });
+
+    it("should ignore `false`", function() {
+      assert.deepEqual(babelPresetEnv.getTargets({
+        uglify: false
+      }), {});
+    });
+
+    it("should ignore `null`", function() {
+      assert.deepEqual(babelPresetEnv.getTargets({
+        uglify: null
+      }), {});
+    });
+  });
+
   describe("isPluginRequired", () => {
     it("returns true if no targets are specified", () => {
       const isRequired = babelPresetEnv.isPluginRequired({}, {});
@@ -173,6 +195,18 @@ describe("babel-preset-env", () => {
       assert(babelPresetEnv.isPluginRequired(targets, plugin) === true);
     });
 
+    it("returns true if uglify is specified as a target", () => {
+      const plugin = {
+        chrome: 50
+      };
+      const targets = {
+        chrome: 55,
+        uglify: true
+      };
+
+      assert(babelPresetEnv.isPluginRequired(targets, plugin) === true);
+    });
+
     it("doesn't throw when specifying a decimal for node", () => {
       const plugin = {
         node: 6