Workaround for broken TypeScript findConfigFilepath under Windows

Author: locobert

README.md

@@ -26,6 +26,7 @@ Portions of this project are heavily based on parts of [vueify](https://github.c
   },
 ```
 
+* Make sure a suitable `tsconfig.json` is present to specify your required TypeScript compiler options
 * Write a test for a Vue.js component
 ```typescript
 /// <reference path='../node_modules/@types/jest/index.d.ts' />
@@ -74,10 +75,12 @@ describe('counter-ts.vue', () => {
 * Use jest as usual, e.g., `npm test -- --watch`
 
 ### Notes
+* This project looks for `tsconfig.json` starting in the directory of the source file and continuing up in the directory tree
+* Only the `compilerOptions` subtree of `tsconfig.json` is used
 * To use `import` with `*.vue` files in TypeScript code, cf. <https://github.com/locoslab/vue-typescript-import-dts>
 * To use TypeScript classes as Vue.js components, cf.
 <https://github.com/locoslab/vue-typescript-component>
-* TypeScript code inline in a `*.vue` file is not supported. We prefer separate files to make use of existing IDE/editor and tooling support for TypeScript files. Instead, import the TypeScript module as follows
+* Inline TypeScript code in a `*.vue` file is not supported. We prefer separate files to make use of existing IDE/editor and tooling support for TypeScript files. Instead, import the TypeScript module as follows
 ```html
 <template>
 ...

preprocessor.js

@@ -1,13 +1,28 @@
 const fs = require('fs')
+const path = require('path')
 
 var defaultBabelOptions = {
 	presets: ['es2015'],
 	plugins: ['transform-runtime']
 }
 
 function ts(src, filePath) {
+	// Microsoft's ts.findConfigFilepath does not work under Windows (hard coded '/' as directory separator)
+	// https://github.com/Microsoft/TypeScript/pull/9625 probably fixes this but is open since July 11th
+	function findConfigFile(filePath) {
+		const testPath = path.join(filePath, 'tsconfig.json')
+		if (fs.existsSync(testPath)) {
+			return testPath
+		} else {
+			const parent = path.dirname(filePath)
+			return parent !== filePath ? findConfigFile(parent) : undefined
+		}
+	}
 	const ts = require('typescript')
-	const tsConfigPath = ts.findConfigFile(filePath, fs.existsSync)
+	const tsConfigPath = findConfigFile(filePath)
+	if (!tsConfigPath) {
+		throw 'tsconfig.json not found for ' + filePath
+	}
 	const tsOptions = require(tsConfigPath)
 	const options = {
 		compilerOptions: tsOptions.compilerOptions,