Speculative fix for #565 (#566)

* Speculative fix for #565

* Added 2.4.1 to the build matrix

* Added 2.4.1 to the build matrix

* Update CHANGELOG.md

Author: johnnyreilly

.travis.yml

@@ -17,4 +17,5 @@ env:
   - [email protected]
   - [email protected]
   - [email protected]
+  - [email protected]
 #  - TYPESCRIPT=typescript@next

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## v2.2.1 - NOT RELEASED YET
 
 - [Report errors in JS(X) files when CheckJS is enabled](https://github.com/TypeStrong/ts-loader/pull/564) - thanks @schmuli!
+- [Cater for change to @types acquisition strategy in TypeScript 2.4.1](https://github.com/TypeStrong/ts-loader/pull/566) - thanks @johnnyreilly
 
 ## v2.2.0
 

appveyor.yml

@@ -8,6 +8,7 @@ environment:
   - TYPESCRIPT: [email protected]
   - TYPESCRIPT: [email protected]
   - TYPESCRIPT: [email protected]
+  - TYPESCRIPT: [email protected]
 #  - TYPESCRIPT: typescript@next
 install:
   - ps: Install-Product node $env:nodejs_version

src/servicesHost.ts

@@ -63,6 +63,12 @@ function makeServicesHost(
          * For @types expansion, these two functions are needed.
          */
         directoryExists: compiler.sys ? (<any> compiler.sys).directoryExists : undefined,
+
+        // The following three methods are necessary for @types resolution from TS 2.4.1 onwards see: https://github.com/Microsoft/TypeScript/issues/16772
+        fileExists: moduleResolutionHost.fileExists,
+        readFile: moduleResolutionHost.readFile,
+        readDirectory: compiler.sys ? (<any> compiler.sys).readDirectory : undefined,
+
         getCurrentDirectory: () => process.cwd(),
 
         getCompilationSettings: () => compilerOptions,