Merge pull request #346 from danger/babel7plus

Bring back the typescript compiler

changelog.md

@@ -8,7 +8,9 @@
 
 * 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
+  happy to keep Danger in a pretty long alpha, till at least Babel 7 is in beta.
+
+  It also still supports using TypeScript via the "`typescript"` module, if you have that installed. - orta
 
 ### 2.0.0-alpha.8
 

dangerfile.ts

@@ -18,7 +18,7 @@ import { distanceInWords } from "date-fns"
 
 // For some reason we're getting type errors on this includes module?
 // Wonder if we could move to the includes function in ES2015?
-import includes from "lodash.includes"
+import * as includes from "lodash.includes"
 const sentence = danger.utils.sentence
 
 schedule(async () => {

source/runner/DangerfileRunner.ts

@@ -7,22 +7,28 @@ import { DangerContext } from "../runner/Dangerfile"
 
 import { NodeVM, NodeVMOptions } from "vm2"
 
+let hasNativeTypeScript = false
 let hasBabel = false
-let hasTypeScript = false
+let hasBabelTypeScript = 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
+  hasNativeTypeScript = 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
+    hasBabelTypeScript = true
   } catch (e) {} // tslint:disable-line
 
   try {
@@ -60,8 +66,9 @@ export async function createDangerfileRuntimeEnvironment(dangerfileContext: Dang
 function compile(code: string, filename: string) {
   const filetype = path.extname(filename)
   let result = code
-
-  if (hasBabel && hasTypeScript && !filename.includes("node_modules") && filetype.startsWith(".ts")) {
+  if (hasNativeTypeScript && !filename.includes("node_modules") && filetype.startsWith(".ts")) {
+    result = typescriptify(code)
+  } else if (hasBabel && hasBabelTypeScript && !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, hasFlow ? ["transform-flow-strip-types"] : [])
@@ -168,6 +175,12 @@ 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, extraPlugins: string[]): string => {
   const babel = require("babel-core") // tslint:disable-line
   const options = babel.loadOptions({})