Frontend Development Guidelines

Code Style

  • the project uses TypeScript to statically analyze code
  • project uses eslint and stylelint to check frontend code. You can manually run via npm run lint
  • Git Hooks (via husky) installed automatically on npm install. They check and try to fix code style if possible, otherwise commit will be rejected
  • if you want IDE integration, you need eslint and stylelint plugin to be installed

CSS Styles

  • now we are migrating to CSS Modules, and this is a recommended way to stylization. A file with styles should be named like component.module.css
  • old component styles use BEM notation (at least it should): block__element_modifier. Also, there are mix classes: block_modifier
  • new way to name CSS selectors is camel-case like blockElemenModifier and use classnames to combine it
  • component base style resides in the component's root directory with a name of component converted to kebab-case. For example, ListComments style is located in ./app/components/list-comments/list-component.tsx
  • any other files should be named also in kebab-case. For example, ./app/utils/get-param.ts


  • imports for TypeScript, JavaScript files should be without extension: ./index, not ./index.ts
  • if the file resides in the same directory or subdirectory, import should be relative: ./types/something
  • otherwise, it should be imported by absolute path relative to src folder like common/store which mapped to ./app/common/store.ts in webpack, tsconfig and Jest


  • project uses jest as test harness
  • Jest checks files that match regex \.(test|spec)\.ts(x?)$, i.e., comment.test.tsx, comment.spec.ts
  • tests are running on push attempt
  • example tests can be found in ./app/store/user/reducers.test.ts, ./app/components/auth-panel/auth-panel.test.tsx

How to add a new locale

Please see this documentation.


  • frontend part being bundled on docker env gets placed on /src/web and is available via http://{host}/web. For example, embed.js entry point will be available at http://{host}/web/embed.js