[5.0.0-alpha.3.0] Can't bundle Typescript

[vcvuwac]

I'd like to use karma-webpack to compile typescript.

• Operating System: Windows 10
• Node Version: v11.9.0
• NPM Version: 6.5.0
• webpack Version: 4.35.2
• karma-webpack Version: 5.0.0-alpha.3.0

Expected Behavior

Successfully complete test.

Actual Behavior

TypeError [ERR_INVALID_ARG_TYPE]: The "data" argument must be one of type string, TypedArray, or DataView. Received type undefined
    at Hash.update (internal/crypto/hash.js:64:11)
    at Object.sha1 (C:\Users\HiICS\Desktop\karmatest\node_modules\karma\lib\utils\crypto-utils.js:9:8)
    at nextPreprocessor (C:\Users\HiICS\Desktop\karmatest\node_modules\karma\lib\preprocessor.js:28:30)
    at processFile (C:\Users\HiICS\Desktop\karmatest\node_modules\karma-webpack\lib\karma-webpack.js:120:5)
    at processTicksAndRejections (internal/process/next_tick.js:81:5)

karma-webpack generates a name of bundle file from .ts path.
https://github.com/webpack-contrib/karma-webpack/blob/eec6dfc9e80413fe957136975034757bdffe9e8e/lib/karma-webpack.js#L84-L87

However it gets a bundle content from a file path generated from .js path.
So, second argument of done() is always undefined.
https://github.com/webpack-contrib/karma-webpack/blob/eec6dfc9e80413fe957136975034757bdffe9e8e/lib/karma-webpack.js#L105-L120

Code

// karma.conf.js
module.exports = function(config) {
  config.set({
    frameworks: ['jasmine'],
    files: ['index.test.ts'],
    preprocessors: {
      '*.ts': ['webpack']
    },
    browsers: ['Chrome'],
    webpack: {
      resolve: { extensions: ['.ts'] },
      module: {
        rules: [
          { test: /\.ts$/, use: ['ts-loader'] }
        ]
      }
    }
  })
}

// index.test.ts
describe("Test", () => it("test", () => expect(true).toBe(true)));

How Do We Reproduce?

See karma.conf.js above. You can install all dependencies by npm i -D karma karma-chrome-launcher karma-jasmine jasmine karma-webpack@5.0.0-alpha.3.0 webpack ts-loader typescript @types/jasmine. This bug is also reproduced if you use mocha. No problem even if tsconfig.json is an empty file.
It's not reproduced in karma-webpack@4.0.2

[naoak]

I made a patch for this issue. Hope this helps anyone.

diff --git a/node_modules/karma-webpack/lib/karma-webpack.js b/node_modules/karma-webpack/lib/karma-webpack.js
index 05a35b2..8740b3a 100644
--- a/node_modules/karma-webpack/lib/karma-webpack.js
+++ b/node_modules/karma-webpack/lib/karma-webpack.js
@@ -113,10 +113,11 @@ function preprocessorFactory(config, emitter) {
   return async function processFile(content, file, done) {
     await controller.bundle();
 
+    const originalFileInfo = path.parse(file.path);
     file.path = normalize(transformPath(file.path)); // eslint-disable-line no-param-reassign
 
-    const bundleContent =
-      controller.bundlesContent[getPathKey(file.path, true)];
+    const pathKey = getPathKey(file.path.replace('.js', originalFileInfo.ext), false) + '.js'
+    const bundleContent = controller.bundlesContent[pathKey];
     done(null, bundleContent);
   };
 }

[codymikol]

To limit confusion, I am combining all threads for webpack 5 / karma6 support over here ==> #475

[codymikol]

v5 is now available