tl;dr
yarn dist
for prod,yarn start
for local development
This directory contains the MetaMask build system, which is used to build the MetaMask Extension such that it can be used in a supported browser.
From the repository root, the build system entry file is located at ./development/build/index.js
.
Several package scripts invoke the build system.
For example, yarn start
creates a watched development build, and yarn dist
creates a production build.
Some of these scripts applies lavamoat
to the build system, and some do not.
For local development, building without lavamoat
is faster and therefore preferable.
The build system is not a full-featured CLI, but rather a script that expects some command line arguments and environment variables. For instructions regarding environment variables, see the main repository readme.
Generally speaking, the build system consists of gulp
tasks that either manipulate static assets or bundle source files using Browserify.
Production-ready zip files are written to the ./builds
directory, while "unpacked" extension builds
are written to the ./dist
directory.
Our JavaScript source files are transformed using Babel, specifically using
the babelify
Browserify transform.
Source file bundling tasks are implemented in the ./development/build/scripts.js
.
Locally implemented Browserify transforms, some of which affect how we write JavaScript, are listed and documented here.
Usage: yarn build <entry-task> [options]
Commands:
yarn build prod Create an optimized build for production environments.
yarn build dev Create an unoptimized, live-reloaded build for local
development.
yarn build test Create an optimized build for running e2e tests.
yarn build testDev Create an unoptimized, live-reloaded build for running
e2e tests.
Options:
--build-type The "type" of build to create. One of: "beta", "main"
[string] [default: "main"]
--lint-fence-files Whether files with code fences should be linted after
fences have been removed by the code fencing transform.
The build will fail if linting fails.
Defaults to `false` if the entry task is `dev` or
`testDev`, and `true` otherwise.
[boolean] [default: <varies>]
--lockdown Whether to include SES lockdown files in the extension
bundle. Setting this to `false` is useful e.g. when
linking dependencies that are incompatible with lockdown.
[boolean] [default: true]
--policy-only Stops the build after generating the LavaMoat policy,
skipping any writes to disk.
[boolean] [deafult: false]
--skip-stats Whether to refrain from logging build progress. Mostly
used internally.
[boolean] [default: false]