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Conveyal's front-end JavaScript tool-belt. Build, run, lint and deploy front-end code.

Table of Contents


We pin mastarm to a specific version of node due to inconsistencies across installation and building when using multiple versions. Node 8 is now required to run mastarm.


With node v8 and npm 5 installed:

$ npm install -g mastarm


Mastarm can be pointed to a directory containing configuration files using the --config flag. It will fall back to files in the configurations/default path of the current working directory if one of the files below does not exist in config folder specified.


This file should contain strings that can be replaced in front-end JavaScript code using envify. Example in Scenario Editor.


This file should contain string messages to be used throughout the application. It will replace process.env.MESSAGES with a string-ified version of the object. Just JSON.parse it on the client to have access to all of your messages.


Settings contain both Mastarm configuration settings and per environment settings to be used in the application and are usually duplicates of what can be passed from the command line. Current Mastarm settings are:

  • cloudfront {String} CloudFront distribution id that will automatically invalidate file paths after they are deployed to S3
  • entries {Array} input:output JavaScript & CSS file pairs
  • env {String} environment override
  • environments {Object} override top level settings (see example)
  • flyle {Boolean} serve map tiles from a local cache for working offline
  • s3bucket {String} bucket to deploy to
  • serve {Boolean} serve client side files via budo


Auto-populate your redux store with this configuration data instead of setting defaults directly in code.


Add a stylesheet that gets @imported at the beginning of your entry stylesheet. This allows you to override styles for specific deployments and use custom CSS properties. Useful for configuration specific images and colors.

CLI Usage

Not all options pertain to all commands. Entries are in the format input/file.js:output/file.js.

$ mastarm --help

  Usage: mastarm [options] [command]


    build [entries...]        Bundle JavaScript & CSS
    commit                    Force intelligent commit messages.
    deploy                    Bundle & Deploy JavaScript & CSS
    flow [command]            Run flow on the current directory.
    format [entries...]       Format JavaScript
    lint                      Lint JavaScript
    lint-messages [paths...]  Check existence of messages used in source code.
    prepublish [entries...]   Transpile JavaScript down to ES5 with Babel
    test [patterns...]        Run tests using Jest
    help [cmd]                display help for [cmd]


    -h, --help               output usage information
    -V, --version            output the version number
    -c, --config <path>      Path to configuration files.
    -e, --env <environment>  Environment to use.
    -m, --minify             Minify built files.
    -O, --outdir <dir>       Publish directory


Compile JS, HTML, CSS, YAML, Markdown into a single .js. Utilizes babel, browserify, budo, and postcss.

$ mastarm build --help

  Usage: mastarm-build [options]


    -h, --help             output usage information
    -F, --flyle            Cache and serve tiles.
    -p, --proxy <address>  Proxy calls through to target address.
    -s, --serve            Serve with budo. Automatically rebuilds on changes.
    -w, --watch            Automatically rebuild on changes.

If no entries are provided, mastarm will use the entries option from your settings.yml config file. If no entries are found, build will not run.

CSS Building

CSS builds occur separately from the browserify build. Any CSS imports into a JavaScript file cause a build error. To build CSS file(s), specify the CSS file(s) as entries in the command. When running in serve or watch mode, the CSS files get automatically rebuilt, but a manual page refresh is necessary.


Utilize best practices when forming a commit message using Commitzen & the Conventional Changelog standard.


Build, push to S3, and invalidate CloudFront in one command. If the static-file-directory flag is set, then mastarm will not build any files with browserify, and instead it will just upload all files in the base level of the specified directory.

$ mastarm deploy --help

Usage: mastarm-deploy [options]

  -m, --minify                   Minify built files.
  -O, --outdir <dir>             Publish directory (default: "")
  --cloudfront <id>              CloudFront Distribution ID to invalidate.
  --s3bucket <bucket>            S3 Bucket to push to.
  --static-file-directory <dir>  Directory of static files to deploy in lieu of building
  -h, --help                     output usage information

Slack Notifications

To enable Slack notifications during the deploy process create a Slack Webhook and add two entries SLACK_WEBHOOK and SLACK_CHANNEL to your env.yml.

SLACK_CHANNEL: '#devops'

MS Teams Notifications

To enable an MS Teams notification upon the completion (successful or not) of the deploy process, create a MS Teams Webhook and add the incoming webhook url as the MS_TEAMS_WEBHOOK key/value to your env.yml.



Run Flow. Must have a .flowconfig in the current working directory and a // @flow annotation at the top of each file you want to check. See the Flow website for documentation.


Format JavaScript code using Prettier. By default it globs all JavaScript files from the current directory and __mocks__, __tests__, bin, lib, and src. If you pass files in it directly it will just use those.

$ mastarm format

To format one file:

$ mastarm format index.js


Lint using Standard and various configurations noted in an internal eslintrc.json file. Everything is passed directly to standard-engine.

$ mastarm lint [paths...]

Optionally pass in a directory (or directories) using the glob pattern. Quote paths containing glob patterns so that they are expanded by standard instead of your shell:

$ mastarm lint "src/util/**/*.js" "test/**/*.js"

Note: by default standard will look for all files matching the patterns: "**/*.js", "**/*.jsx". Always quote the globs. Needed when used as an npm command.


Transpile a library using Babel and our custom config. Usually used as a prepublish step for libraries written in ES6+ that will be published to NPM. Pass it a directory and it will look for .js files to transpile.

$ mastarm prepublish lib:build


Run the Jest test runner on your project.

$ mastarm test

Usage: test [options] [patterns...]

Run tests using Jest


-c, --config <path>                     Path to configuration files. (default: path.join(process.cwd() + '/configurations/default'))
-e, --env <environment>                 Environment to use.
-u, --update-snapshots                  Force update of snapshots. USE WITH CAUTION.
--coverage                              Run Jest with coverage reporting
--coverage-paths <paths>                Extra paths to collect code coverage from in addition to the mastarm default of `lib/**/*.js`
--custom-config-file <path>             Override the Jest config with the values found in a file path relative to the current working directory
--force-exit                            Force Jest to exit after all tests have completed running.
--jest-cli-args <args>                  Extra arguments to pass directly to the Jest Cli. Make sure to encapsulate all extra arguments in quotes
--no-cache                              Run Jest without cache (defaults to using cache)
--run-in-band                           Run all tests serially in the current process. This is always set to true while running on in a continuous integration environment.
--setup-files <paths>                   Setup files to run before each test
--test-environment <env>                Jest test environment to use (Jest default is jsdom)
--test-path-ignore-patterns <patterns>  File patterns to ignore when scanning for test files
-h, --help                              output usage information

By default, mastarm will run Jest with most of the defaults in place. The defaults that mastarm adds include:

  • some transforms needed to read certain .js files and also YAML files.
  • ignoring the test path directory __tests__/test-utils
  • setting the testURL to http://localhost:9966
  • turning on notifications of test completion

If the coverage flag is set to true, mastarm will automatically generate coverage reports of all .js files in the lib folder and will save the reports to the coverage folder.

The patterns argument will make Jest run only tests whose filename match the provided pattern.

There are a number of ways to set the Jest config. The first is by adding a jest object to the package.json of the project. A number of other mastarm options will override the config. And finally, it is possible to use a custom config file (either .json or .js) via the --custom-config-file option. The config values are set and potentially overridden in the following order:

  1. mastarm defaults.
  2. Options in the jest object of the project's package.json file.
  3. The values specified in the mastarm arguments --coverage-paths, --setup-files, --test-environment and --test-path-ignore-patterns
  4. Options set in a custom config file specified in the mastarm argument --custom-config-file.

Here is an example of how to set the config using a custom file:

mastarm test --custom-config-file __tests__/test-utils/mocks/mock-jest-config.json

It is also possible to override any Jest CLI Options by setting the --jest-cli-args flag. Ex:

mastarm test --jest-cli-args "--json --outputFile e2e-test-results/results.json"


$ mastarm lint-messages

Usage: lint-messages [options] [paths...]

Check that all messages used in source code are present in config. Pass in path to source file(s). Set the config with --config.

This checks to ensure that all of the messages referenced in JS code are defined in the messages.yml file. It defaults to using the messages in configurations/default/messages.yml, however a different config can be specified with --config. By default it will check the JS files in lib, but you can also pass in an arbitrary number of paths to directories or files to lint.

lint-messages is somewhat opinionated about how messages should be used in code. They should be imported from a local module called messages, and referred to using dot notation. It will work regardless of whether you import the top-level messages object or named children. The following import strategies all work:

import messages from '../utils/messages'
import msgs from './messages'
import { analysis } from './messages'
import msgs, { project as proj } from '../messages'
import {analysis, project as proj}, msgs from '../messages'

and permutations thereof. Messages should be referred to directly from these top-level imports, i.e. you should not refer to messages like this:

import messages from './messages'
const { analysis, project } = messages
return analysis.newScenario

but the following is fine:

import { analysis } from './messages'
return analysis.newScenario


npm i mastarm

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  • trevorgerhardt
  • evansiroky