Make TypeScript/Flow get optionally applied

.babelrc

@@ -1,11 +1,4 @@
 {
-    "presets": [
-        "es2015",
-        "stage-3"
-    ],
-    "plugins": [
-        "transform-flow-strip-types",
-        "syntax-async-functions",
-        "transform-regenerator"
-    ]
+  "presets": ["es2015", "stage-3"],
+  "plugins": ["syntax-async-functions", "transform-regenerator"]
 }

changelog.md

@@ -4,6 +4,12 @@
 
 // TODO
 
+### 2.0.0-alpha.9
+
+* Uses the Babel 7 alpha for all source compilation with JS, Flow+JS and TS. This worked without any changes to our
+  internal infra which is pretty awesome. All TS tests passed. Babel 7 is still in alpha, but so is Danger 2.0 - so I'm 
+  happy to keep Danger in a pretty long alpha, till at least Babel 7 is in beta. - orta
+
 ### 2.0.0-alpha.8
 
 * Uses the GitHub `diff_url` instead of the `diff` version header, as it conflicted with Peril - orta

package.json

@@ -57,6 +57,16 @@
     "@types/debug": "0.0.29",
     "@types/jest": "^20.0.0",
     "@types/node-fetch": "^1.6.6",
+    "babel-cli": "7.0.0-alpha.19",
+    "babel-core": "7.0.0-alpha.19",
+    "babel-plugin-syntax-async-functions": "7.0.0-alpha.19",
+    "babel-plugin-transform-flow-strip-types": "7.0.0-alpha.19",
+    "babel-plugin-transform-regenerator": "7.0.0-alpha.19",
+    "babel-plugin-transform-typescript": "7.0.0-alpha.19",
+    "babel-polyfill": "7.0.0-alpha.19",
+    "babel-preset-es2015": "7.0.0-alpha.19",
+    "babel-preset-stage-3": "7.0.0-alpha.19",
+    "babel-traverse": "7.0.0-alpha.19",
     "danger-plugin-yarn": "^0.2.9",
     "date-fns": "^1.28.3",
     "husky": "^0.14.0",
@@ -69,19 +79,9 @@
     "ts-node": "^3.2.1",
     "tslint": "^5.3.0",
     "tslint-config-prettier": "^1.0.0",
-    "typedoc": "orta/typedoc#0.5.10-no-types",
-    "typescript": "^2.4.2"
+    "typedoc": "orta/typedoc#0.5.10-no-types"
   },
   "dependencies": {
-    "babel-cli": "7.0.0-alpha.19",
-    "babel-core": "7.0.0-alpha-19",
-    "babel-plugin-syntax-async-functions": "7.0.0-alpha.19",
-    "babel-plugin-transform-flow-strip-types": "7.0.0-alpha.19",
-    "babel-plugin-transform-regenerator": "7.0.0-alpha.19",
-    "babel-polyfill": "7.0.0-alpha.19",
-    "babel-preset-es2015": "7.0.0-alpha.19",
-    "babel-preset-stage-3": "7.0.0-alpha.19",
-    "babel-traverse": "7.0.0-alpha-19",
     "chalk": "^2.0.0",
     "commander": "^2.9.0",
     "debug": "^3.0.0",
@@ -97,6 +97,7 @@
     "parse-link-header": "^1.0.1",
     "pinpoint": "^1.1.0",
     "rfc6902": "^1.3.0",
+    "typescript": "^2.4.2",
     "vm2": "patriksimek/vm2",
     "voca": "^1.2.0"
   },

source/runner/DangerfileRunner.ts

@@ -7,20 +7,28 @@ import { DangerContext } from "../runner/Dangerfile"
 
 import { NodeVM, NodeVMOptions } from "vm2"
 
-let hasTypeScript = false
 let hasBabel = false
+let hasTypeScript = false
+let hasFlow = false
 
 declare const regeneratorRuntime: any
 
 // You know you're being a dangerous badass when you have this many linter disables. Deal with it.
-try {
-  require.resolve("typescript") // tslint:disable-line
-  hasTypeScript = true
-} catch (e) {} // tslint:disable-line
+
 try {
   require.resolve("babel-core") // tslint:disable-line
   require("babel-polyfill") // tslint:disable-line
   hasBabel = true
+
+  try {
+    require.resolve("babel-plugin-transform-typescript") // tslint:disable-line
+    hasTypeScript = true
+  } catch (e) {} // tslint:disable-line
+
+  try {
+    require.resolve("babel-plugin-transform-flow-strip-types") // tslint:disable-line
+    hasFlow = true
+  } catch (e) {} // tslint:disable-line
 } catch (e) {} // tslint:disable-line
 
 /**
@@ -52,10 +60,11 @@ export async function createDangerfileRuntimeEnvironment(dangerfileContext: Dang
 function compile(code: string, filename: string) {
   const filetype = path.extname(filename)
   let result = code
-  if (hasTypeScript && filetype.startsWith(".ts")) {
-    result = typescriptify(code)
+
+  if (hasBabel && hasTypeScript && !filename.includes("node_modules") && filetype.startsWith(".ts")) {
+    result = babelify(code, filename, ["transform-typescript"])
   } else if (hasBabel && !filename.includes("node_modules") && filetype.startsWith(".js")) {
-    result = babelify(code, filename)
+    result = babelify(code, filename, hasFlow ? ["transform-flow-strip-types"] : [])
   }
 
   return result
@@ -159,20 +168,17 @@ export function cleanDangerfile(contents: string): string {
   return contents.replace(es6Pattern, "// Removed import").replace(requirePattern, "// Removed require")
 }
 
-const typescriptify = (content: string): string => {
-  const ts = require("typescript") // tslint:disable-line
-  let result = ts.transpileModule(content, {})
-  return result.outputText
-}
-
-const babelify = (content: string, filename: string): string => {
+const babelify = (content: string, filename: string, extraPlugins: string[]): string => {
   const babel = require("babel-core") // tslint:disable-line
+  const options = babel.loadOptions({})
+
   const fileOpts = {
     filename,
     filenameRelative: filename,
     sourceMap: false,
     sourceFileName: null,
     sourceMapTarget: null,
+    plugins: [...extraPlugins, ...options.plugins],
   }
 
   const result = babel.transform(content, fileOpts)

yarn.lock

@@ -243,7 +243,7 @@ babel-code-frame@^6.22.0, babel-code-frame@^6.8.0:
     esutils "^2.0.2"
     js-tokens "^3.0.0"
 
-babel-core@7.0.0-alpha-19, babel-core@7.0.0-alpha.19:
+babel-core@7.0.0-alpha.19:
   version "7.0.0-alpha.19"
   resolved "https://registry.yarnpkg.com/babel-core/-/babel-core-7.0.0-alpha.19.tgz#6127e8dcbe2fa1ce0864c7698aceed369d3b1b9d"
   dependencies:
@@ -479,6 +479,10 @@ babel-plugin-syntax-optional-catch-binding@7.0.0-alpha.19:
   version "7.0.0-alpha.19"
   resolved "https://registry.yarnpkg.com/babel-plugin-syntax-optional-catch-binding/-/babel-plugin-syntax-optional-catch-binding-7.0.0-alpha.19.tgz#15479086d1c18ef63b02491ff96691116f17bb35"
 
+babel-plugin-syntax-typescript@7.0.0-alpha.19:
+  version "7.0.0-alpha.19"
+  resolved "https://registry.yarnpkg.com/babel-plugin-syntax-typescript/-/babel-plugin-syntax-typescript-7.0.0-alpha.19.tgz#fc5876863db297549f5d840d248eac3310241f84"
+
 babel-plugin-transform-async-generator-functions@7.0.0-alpha.19:
   version "7.0.0-alpha.19"
   resolved "https://registry.yarnpkg.com/babel-plugin-transform-async-generator-functions/-/babel-plugin-transform-async-generator-functions-7.0.0-alpha.19.tgz#9e9b7d0aee6b09f58756c484bf3f472225a551c2"
@@ -670,6 +674,12 @@ babel-plugin-transform-strict-mode@^6.24.1:
     babel-runtime "^6.22.0"
     babel-types "^6.24.1"
 
+babel-plugin-transform-typescript@7.0.0-alpha.19:
+  version "7.0.0-alpha.19"
+  resolved "https://registry.yarnpkg.com/babel-plugin-transform-typescript/-/babel-plugin-transform-typescript-7.0.0-alpha.19.tgz#9b06c066393d6752e6e539e8b0b5929a78feb5b1"
+  dependencies:
+    babel-plugin-syntax-typescript "7.0.0-alpha.19"
+
 babel-plugin-transform-unicode-property-regex@^2.0.2:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/babel-plugin-transform-unicode-property-regex/-/babel-plugin-transform-unicode-property-regex-2.0.3.tgz#db13fe12e7380dd6ce0e9206cff3eb4116483ece"
@@ -802,7 +812,7 @@ babel-traverse@6.12.0:
     invariant "^2.2.0"
     lodash "^4.2.0"
 
-babel-traverse@7.0.0-alpha-19, babel-traverse@7.0.0-alpha.19:
+babel-traverse@7.0.0-alpha.19:
   version "7.0.0-alpha.19"
   resolved "https://registry.yarnpkg.com/babel-traverse/-/babel-traverse-7.0.0-alpha.19.tgz#083f3f00a413fd9ec38383c0d5ae79511d9ed53d"
   dependencies: