Move babel-preset-env-standalone to the monorepo. (#6438)

experimental/babel-preset-env-standalone/README.md

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+@babel/preset-env-standalone
+=================
+
+@babel/preset-env-standalone is a standalone build of [@babel/preset-env](https://babeljs.io/docs/plugins/preset-env) for use in non-Node.js environments, including browsers.
+
+Installation
+============
+
+There are several ways to use @babel/preset-env-standalone. Pick whichever one you like:
+
+- Use it via UNPKG: https://unpkg.com/@babel/preset-env-standalone@7/babel-preset-env.min.js. This is a simple way to embed it on a webpage without having to do any other setup.
+- Install via NPM: `npm install --save @babel/preset-env-standalone`
+- Manually grab `babel-preset-env.js` and/or `babel-preset-env.min.js`:
+  * Download archived source code from the [GitHub releases page](https://github.com/babel/babel/releases).
+  * Unpack it.
+  * Grab `babel-preset-env.js` and/or `babel-preset-env.min.js` from the `experimental/babel-preset-env-standalone`.
+
+Usage
+=====
+
+Load `babel-preset-env.js` or `babel-preset-env.min.js` in your environment, **along with babel-standalone**. This is important: You need to load Babel too! It will be registered as an available preset of the @babel/standalone.
+
+Then, just use it like any other preset:
+
+```js
+Babel.transform(code, {
+  presets: [
+    ["@babel/preset-env", {
+      "targets": {
+        "browsers": "last 1 safari version"
+      },
+      useBuiltIns: "usage"
+    }]
+  ]
+});
+```

experimental/babel-preset-env-standalone/package.json

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+{
+  "name": "@babel/preset-env-standalone",
+  "version": "7.0.0-beta.5",
+  "description": "Standalone build of babel-prest-env for use in non-Node.js environments.",
+  "main": "babel-preset-env.js",
+  "files": [
+    "babel-preset-env.js",
+    "babel-preset-env.min.js",
+    "src"
+  ],
+  "devDependencies": {
+    "@babel/plugin-transform-new-target": "7.0.0-beta.5",
+    "@babel/preset-env": "7.0.0-beta.5",
+    "@babel/standalone": "7.0.0-beta.5",
+    "mock-require": "^2.0.2"
+  },
+  "keywords": [
+    "babel",
+    "babel-preset-env",
+    "babeljs",
+    "6to5",
+    "transpile",
+    "preset",
+    "standalone",
+    "transpiler"
+  ],
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/babel/babel/issues"
+  },
+  "homepage": "https://github.com/babel/babel/packages/babel-preset-env-standalone#readme",
+  "jest": {
+    "transformIgnorePatterns": [
+      "/node_modules/",
+      "babel-preset-env.js"
+    ]
+  }
+}

experimental/babel-preset-env-standalone/src/available-plugins.js

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+import { availablePlugins, registerPlugin } from "@babel/standalone";
+
+const notIncludedPlugins = {
+  "transform-new-target": require("@babel/plugin-transform-new-target"),
+};
+
+Object.keys(notIncludedPlugins).forEach(pluginName => {
+  if (!availablePlugins[pluginName]) {
+    registerPlugin(pluginName, notIncludedPlugins[pluginName]);
+  }
+});
+
+export default availablePlugins;

experimental/babel-preset-env-standalone/src/caniuse-lite-regions.js

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+module.exports = {};

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

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+/* global VERSION */
+
+import { registerPreset } from "@babel/standalone";
+import babelPresetEnv from "@babel/preset-env";
+
+registerPreset("env", babelPresetEnv);
+
+export const version = VERSION;

experimental/babel-preset-env-standalone/test/babel-preset-env.js

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+const assert = require("assert");
+const mock = require("mock-require");
+const Babel = require("@babel/standalone/babel");
+mock("Babel", Babel);
+require("../babel-preset-env");
+
+describe("babel-preset-env-standalone", () => {
+  it("works w/o targets", () => {
+    const output = Babel.transform("const a = 1;", {
+      presets: ["env"],
+    }).code;
+    assert.equal(output, "var a = 1;");
+  });
+
+  it("doesn't transpile `const` with chrome 60", () => {
+    const output = Babel.transform("const a = 1;", {
+      presets: [
+        [
+          "env",
+          {
+            targets: {
+              chrome: 60,
+            },
+          },
+        ],
+      ],
+    }).code;
+    assert.equal(output, "const a = 1;");
+  });
+
+  it("transpiles `const` with chrome 60 and preset-es2015", () => {
+    const output = Babel.transform("const a = 1;", {
+      presets: [
+        [
+          "env",
+          {
+            targets: {
+              chrome: 60,
+            },
+          },
+        ],
+        "es2015",
+      ],
+    }).code;
+    assert.equal(output, "var a = 1;");
+  });
+
+  it("uses transform-new-targets plugin", () => {
+    const output = Babel.transform("function Foo() {new.target}", {
+      presets: ["env"],
+    }).code;
+    assert.equal(
+      output,
+      "function Foo() {\n  this instanceof Foo ? this.constructor : void 0;\n}",
+    );
+  });
+});