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title: '@tramvai/cli' sidebar_label: 'base' sidebar_position: 1

Tramvai CLI

CLI interface for resolving actual problems and tasks of frontend CI. Reduces complexity of setting up webpack, typescript, babel, postcss and other tools.

@tramvai/cli may build projects to production, run code in development mode with automatic rebuilds, project analyze and code generation


Global installation on the developer machine. After that the new command tramvai will be available in terminal.

npm i -g @tramvai/cli

Local installation to the project

npm i --save-dev @tramvai/cli



After any command you can pass --help string, e.g. tramvai --help or tramvai start --help. After that you will see description of the command and its options.

  • tramvai new - generate new tramvai app with @tramvai/cli
  • tramvai start - run app in the development mode
  • tramvai start-prod - run app in development mode, but code will be build in the production mode
  • tramvai build - build an app for server and client
  • tramvai static - generate static HTML for application pages
  • tramvai analyze - analyze bundle size
  • tramvai generate - code generation for different components. E.g. new projects, react components, actions and etc.
  • tramvai update - update @tramvai/cli and all of the @tramvai and @tramvai-tinkoff dependencies in the project. This command additionally executes dependency deduplication and code migrations
  • tramvai add - add @tramvai or @tramvai-tinkoff dependency to the app. This command additionally executes dependency deduplication and code migrations


Notifications settings

Inside tramvai.json the settings for the notification can be specified at path notifications. Parameters are passed to webpack-build-notifier. You can specify global configuration or a specific configuration either for client or server build.

  "notifications": {
    "suppressSuccess": "always",
    "server": {
      "suppressWarning": true
    "client": {
      "activateTerminalOnError": true

CSS class names generation settings

Name generation is configured via the options cssLocalIdentNameDev and cssLocalIdentNameProd (common option cssLocalIdentName might be used to specify settings for both prod and dev).

  "postcss": {
    "cssLocalIdentName": "[hash:base64:5]" // default value (deprecated)


  "postcss": {
    "cssLocalIdentName": {
      "development": "[name]__[local]_[minicss]", // available values see in the docs to [css-loader](https://github.com/webpack-contrib/css-loader)
      "production": "[minicss]" // additionally new tag `minicss` can be used for the generating minimal css names. Based on [article](https://dev.to/denisx/reduce-bundle-size-via-one-letter-css-classname-hash-strategy-10g6)

CSS modules processing

By default, all *.css imports will be processed as CSS Modules.

IF you want to disable Modules for some files, for example with global styles, you can do it by adding cssModulePattern regexp to the config:

  "postcss": {
    // CSS Modules processing will be skipped for *.global.css files
    "cssModulePattern": "^(?!.*global\\.css$).*$"

Polyfills for the standard NodeJS modules

By default, webpack starting with 5th version, do not add polyfills to browser bundle when using nodejs standard modules in the browser code, e.g. when using crypto, path, process, buffer, etc.

@tramvai/cli explicitly adds polyfills for path and process modules as these modules are often used and lightweighted.

Checking TypeScript types

Checking types is enabled by flag checkAsyncTs.

When running tramvai start ts compilation and type checks will be executed.

Inside tramvai.json

"checkAsyncTs": {
  "failOnBuild": true, // optional
  "pluginOptions": {} // optional

failOnBuild adds type checks when running tramvai build. This way build will fail in case of wrong types.

pluginOptionslist of the additional options for the plugin fork-ts-checker-webpack-plugin

If you want to override path to tsconfig through pluginOptions.tsconfig the option should be specified relative to the @tramvai/cli folder itself e.g. node_modules/@tramvai/cli. By default tsconfig is expected to be in the project root directory: <rootDir>/tsconfig.json

Deduplication of modules

Option dedupe controls the settings of plugin for the deduplication process. Available options are:

  • "equality" - uses strict version comparison. Dedupes modules in node_modules with equal package version that are imported from different sources. E.g. imports for node_modules/package/index.js and node_modules/nested-package/node_modules/package/index.js are deduped into a single node_modules/package/index.js import whilst without dedupe it will bundle two files as separate modules.
  • "semver" - compares version of packages based on semver. It can dedupe all of the imports with the same major version and any of the minor and patch versions. E.g. next versions will be deduped: from 1.14.0 and 1.16.2 to 1.16.2, from 0.14.1 and 0.16.5 to 0.16.5, whilst versions 0.0.2 and 0.0.5 will be left without deduplication.

Debug an app

While developing sometimes it is needed to debug nodejs app directly so see CPU, memory consumptions etc. To do it the options --debug might be passed to commands start and start-prod which do next:

  • enables source maps for build on client and server
  • starts the server process with the flag --inspect.

After that you can open debugger in the chrome devtools - chrome://inspect

Webpack Logs

It is possible to get verbose output almost on every cli command where it is using webpack.

To do this, you should pass --verboseWebpack option to command. Check availability of option with help command.

It will pass { logging: 'verbose', loggingDebug: true } to webpack stats config.
Also, it will turn on infrastructureLogging for webpack with options { level: 'verbose', debug: /webpack/ }.

Source Maps

webpack offers several kind of sourcemap qualities. Some of the examples are:

  1. Source code - the code before transpilation and bundling. Snapshot of the source code, splitted by modules
  2. Transformed code - the code after transpilation by loaders (etc. babel-loader), splitted by modules
  3. Generated code - the code after transpilation and bundling, splitted by modules. Every import and exported are replaced by webpack wrapper code

For development source maps for transformed or generated code is used as it is more performant and shows the exact code that is executed in the target environment. The main differences from the debugging without sourcemaps is that code has links to modules to original source files.

tramvai generates big single bundle with server code and that's why it is preferred to not include sourcemaps in the code itself and put it to the separate .js.map file.


By default in development mode for browser is used the fastest sourcemaps (devtool: "eval" in webpack config), while for server no sourcemaps is used.

Flag --debug enables sourcemap generation for the client and server code.

Also, tramvai.json option sourceMap enables sourcemap generation both for browser and server code.

Also, tramvai.json option webpack allows set one of the following values for the devtool option in webpack config: eval-cheap-module-source-map, eval-cheap-source-map, eval-source-map - both for browser and server code.


By default, sourcemaps are disabled both for the client and server code in production mode.

Flag --debug enables sourcemaps generation for the client and server code.

Also, tramvai.json option sourceMap enables sourcemap generation both for browser and server code.


Configuration is provided through json-file with the name tramvai.json in the root of the single-application/monorepo

How to

Code generation

For make life easier for developers @tramvai/cli has ability to automatically generate code with template. For running code generator use command tramvai generate and pick up one of the options available to generate that entity:

  • action
  • bundle
  • reducer
  • page
  • component
  • module

After that template files will be generated

Generate new project

For the quick start of new project you can use command tramvai new that will generate new base project with the tramvai and tramvai-cli

  • install tramvai-cli globally
  • enter command tramvai new NAME_YOUR_APP in the shell
  • choose options based on your preferences: monorepo or multirepo, CI integration and testing framework

After command execution and dependency installation new project will be ready to use

How to run nodejs app in debug mode?

Add flag --debug when running app

tramvai start my-app --debug

Then open chrome devTools, click on NodeJs logo in the upper left corner. New window with the nodejs devtools will be opened that allows to debug memory and cpu usage, debug code and take the performance profiles.

Get details for deprecated and warning logs

It might be useful to get the stacktraces of some of the warnings.

E.g., while running app if you see logs like this

(node:2898) DeprecationWarning: ...
(Use `node --trace-deprecation ...` to show where the warning was created)

You may add flag --trace in order to run nodejs server with the additional options.

tramvai start my-app --trace

After that these logs will be printed with their stacktraces

How to use browserstack for testing

To get access to browserstack just type command /bs in slack

Run app as usual with tramvai start command and follow the browsertack instruction for the local development. If everything were done right you will be able to get access to localhost inside browserstack and test your app through it.

How to test app on mobile or other device in local network

Both devices one that running the app and one for testing must reside in the same network.

For setting access through local network follow next steps:

  1. figure out the ip of the machine that runs app
  2. run command tramvai start with flag --staticHost with value of the ip address that was resolved on previous step (e.g. tramvai start tincoin --staticHost
  3. from the testing device open the new page in the browser and use the ip address from the previous step as domain name

When calling @tramvai/cli using npm you need to pass -- before any additional arguments, e.g. command should look similar to this npm start -- --staticHost

How to enable paths mapping

In case you want to use special imports instead of pure relative paths in your code.

More details and examples you can find in typescript documentation:

@tramvai/cli will reuse options baseUrl and paths from the app's tsconfig.json to provide path mapping functionality.

How to pass Node.js options

You can use NODE_OPTIONS env variable, e.g.:

NODE_OPTIONS="--max_semi_space_size=64" tramvai start-prod {appName}

How to get CPU profile of @tramvai/cli work?

Run application server or production build with env variable TRAMVAI_CPU_PROFILE:

TRAMVAI_CPU_PROFILE=1 tramvai build {appName}

Then, file with tramvai-cli.${Date.now()}.cpuprofile name will be generated in current working directory.

You can open this trace in Chrome DevTools - chrome://inspect, "Open dedicated DevTools for Node", Performance tab.

How to enable production profiling for React

TRAMVAI_REACT_PROFILE=1 tramvai build {appName}
# or
TRAMVAI_REACT_PROFILE=1 tramvai start-prod {appName}

After that, you can use the React DevTools Profiler in the same way as you would in development.

WARNING: The size of the bundle will be larger, because mangling is disabled for such builds. Do not use this env variable for production environment.





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