{"id":11202,"library":"karma-typescript-preprocessor","title":"Karma TypeScript Preprocessor","description":"This package, `karma-typescript-preprocessor`, provides a Karma runner plugin designed to compile TypeScript files on the fly during unit testing. It integrates directly into the Karma configuration, allowing developers to test TypeScript code without a separate, explicit compilation step prior to running tests. The package is currently at version 0.4.0, with its last update occurring approximately seven years ago. Given its age, it is no longer actively maintained and may not support recent TypeScript versions or Karma features. While it offered configurable TypeScript compiler options like `target`, `module`, and `sourceMap` directly within `karma.conf.js`, its primary differentiator was simplifying test setups by handling TypeScript compilation internally, contrasting with the more feature-rich and actively maintained `karma-typescript` package which offers bundling, coverage remapping, and broader framework support.","status":"abandoned","version":"0.4.0","language":"javascript","source_language":"en","source_url":"ssh://git@github.com/sergeyt/karma-typescript-preprocessor","tags":["javascript","karma-plugin","karma-preprocessor","typescript"],"install":[{"cmd":"npm install karma-typescript-preprocessor","lang":"bash","label":"npm"},{"cmd":"yarn add karma-typescript-preprocessor","lang":"bash","label":"yarn"},{"cmd":"pnpm add karma-typescript-preprocessor","lang":"bash","label":"pnpm"}],"dependencies":[{"reason":"Runtime peer dependency; this package is a plugin for Karma.","package":"karma","optional":false},{"reason":"Runtime peer dependency; required for TypeScript compilation.","package":"typescript","optional":false}],"imports":[{"note":"This package is a Karma plugin, configured in `karma.conf.js`. The preprocessor is referenced by its short name, 'typescript', not the full package name.","wrong":"import { TypescriptPreprocessor } from 'karma-typescript-preprocessor';","symbol":"preprocessors configuration","correct":"config.set({\n  preprocessors: {\n    '**/*.ts': ['typescript']\n  }\n});"},{"note":"This object holds compiler options and file transformation logic specific to the preprocessor.","symbol":"typescriptPreprocessor configuration object","correct":"config.set({\n  typescriptPreprocessor: {\n    options: { target: 'ES5' },\n    transformPath: function(path) {\n      return path.replace(/\\.ts$/, '.js');\n    }\n  }\n});"}],"quickstart":{"code":"/**\n * karma.conf.js\n * Configuration for karma-typescript-preprocessor.\n */\nmodule.exports = function(config) {\n  config.set({\n    // Base path that will be used to resolve all relative paths for files and exclude.\n    basePath: '',\n\n    // Frameworks to use\n    // available frameworks: https://npmjs.org/browse/keyword/karma-framework\n    frameworks: ['jasmine'], // Example: using Jasmine testing framework\n\n    // List of files / patterns to load in the browser\n    files: [\n      'src/**/*.ts', // Your TypeScript source files\n      'test/**/*.ts' // Your TypeScript test files\n    ],\n\n    // Preprocess matching files before serving them to the browser\n    // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor\n    preprocessors: {\n      '**/*.ts': ['typescript']\n    },\n\n    // Configuration for the TypeScript preprocessor\n    typescriptPreprocessor: {\n      options: {\n        sourceMap: true, // (optional) Generates corresponding .map file.\n        target: 'ES5',  // (optional) Specify ECMAScript target version: 'ES3' (default), or 'ES5'\n        module: 'amd', // (optional) Specify module code generation: 'commonjs' or 'amd'\n        noImplicitAny: true, // (optional) Warn on expressions and declarations with an implied 'any' type.\n        removeComments: true // (optional) Do not emit comments to output.\n      },\n      // Function to transform filenames, e.g., .ts to .js\n      transformPath: function(path) {\n        return path.replace(/\\.ts$/, '.js');\n      }\n    },\n\n    // Test results reporter to use\n    // possible values: 'dots', 'progress'\n    // available reporters: https://npmjs.org/browse/keyword/karma-reporter\n    reporters: ['progress'],\n\n    // Web server port\n    port: 9876,\n\n    // Enable / disable colors in the output (reporters and logs)\n    colors: true,\n\n    // Level of logging\n    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG\n    logLevel: config.LOG_INFO,\n\n    // Enable / disable watching file and executing tests whenever any file changes\n    autoWatch: true,\n\n    // Start these browsers\n    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher\n    browsers: ['Chrome'],\n\n    // Continuous Integration mode\n    // if true, Karma captures browsers, runs the tests and exits\n    singleRun: false,\n\n    // Concurrency level\n    // how many browser should be started simultaneous\n    concurrency: Infinity\n  });\n};\n","lang":"javascript","description":"Demonstrates a complete `karma.conf.js` setup for `karma-typescript-preprocessor`, including file patterns, preprocessor declaration, and custom TypeScript compiler options like `target` and `module`."},"warnings":[{"fix":"Migrate to an actively maintained alternative like `karma-typescript` which provides broader support for modern TypeScript, bundling, and coverage.","message":"This package has been abandoned for approximately seven years and is no longer maintained. It will not support modern TypeScript features (e.g., decorators, newer ES versions, module resolution changes) or recent Karma versions, which itself has been deprecated. Using it with current ecosystems is likely to lead to compilation errors or unexpected behavior.","severity":"breaking","affected_versions":">=0.4.0"},{"fix":"Always explicitly set the `target` option in `typescriptPreprocessor.options` to an appropriate modern ECMAScript version (e.g., 'ES2015', 'ESNext') that matches your project's requirements.","message":"The default TypeScript `target` is 'ES3', which is extremely outdated. If not explicitly configured, compiled output will be for an ancient JavaScript environment, potentially breaking modern code or tests.","severity":"gotcha","affected_versions":">=0.1.0"},{"fix":"Be aware of the inlined source map behavior. For complex setups or specific debugging workflows, consider if `karma-typescript-preprocessor` is the right choice, as other preprocessors might offer external source map generation.","message":"Source maps are inlined as data-URIs when `sourceMap: true` is enabled. While convenient for simple debugging, this might increase file size or complicate integration with advanced debugging tools that expect external `.map` files.","severity":"gotcha","affected_versions":">=0.1.0"},{"fix":"Set `module: 'commonjs'` or `module: 'esnext'` if your project or test environment uses those module systems. Ensure your Karma setup correctly handles module loading for the chosen option.","message":"The `module` option in `typescriptPreprocessor.options` defaults to `amd` if omitted. This assumes an AMD loader (like RequireJS) is present in your test environment. If your project uses CommonJS or ES Modules and no AMD loader, your tests will likely fail to load or execute.","severity":"breaking","affected_versions":">=0.1.0"},{"fix":"Evaluate the risk and consider migrating to actively maintained alternatives. If continued use is unavoidable, ensure thorough security scanning of your project's dependencies.","message":"As an abandoned package, `karma-typescript-preprocessor` presents a supply chain security risk. It will not receive patches for newly discovered vulnerabilities in its own code or its transitive dependencies.","severity":"gotcha","affected_versions":">=0.1.0"}],"env_vars":null,"last_verified":"2026-04-19T00:00:00.000Z","next_check":"2026-07-18T00:00:00.000Z","problems":[{"fix":"Ensure `karma-typescript-preprocessor` is installed: `npm install --save-dev karma-typescript-preprocessor`. Also, verify that `typescript` is installed as a dependency (`npm install --save-dev typescript`). Check your `karma.conf.js` to confirm `preprocessors: { '**/*.ts': ['typescript'] }` is correctly configured.","cause":"The `karma-typescript-preprocessor` package or its dependency `typescript` is not installed, or Karma cannot find the preprocessor definition.","error":"ERROR [preprocessor]: Can not load \"typescript\" preprocessor!"},{"fix":"Review the `typescriptPreprocessor.options` in `karma.conf.js` to ensure `target`, `module`, and other compiler options align with your project. If using modern TypeScript, consider migrating to a more up-to-date Karma TypeScript preprocessor like `karma-typescript`.","cause":"The TypeScript compiler version or configuration used by the preprocessor (version 0.4.0) is incompatible with your project's TypeScript code, or it's missing `@types` declarations. This preprocessor is very old and likely struggles with modern TS syntax or libraries.","error":"TSxxxx: Cannot find name '...' / Property '...' does not exist on type '...'."},{"fix":"If targeting browsers without a module loader, set `module: 'none'` or ensure an AMD/CommonJS loader (e.g., RequireJS for AMD, a bundler for CommonJS) is included in your Karma `files` array before your compiled test code.","cause":"This error typically occurs when the `module` option in `typescriptPreprocessor.options` is set to `amd` or `commonjs` respectively, but the test environment (browser) lacks the corresponding module loader.","error":"ReferenceError: define is not defined / require is not defined"}],"ecosystem":"npm"}