This is our playbook. It is the foundation that allows us to architect & design systems that move our client projects forward. In it, you will find practical approaches for building frontend & backend javascript applications. This is a living document, and we intend to share our knowledge as we continue to work towards making the web a better place.
A unified development effort should use a single infrastructure to control all similar projects.
Our frontend infrastructure is based around webpack builds, but most of the guidelines / goals apply to any build tool.
Webpack has a rich plugin ecosystem, including both core and open source modules. Webpack also has a straight forward interface to write your own plugins.
A short list of plugin recommendations for best frontend performance include:
| Plugin | Recommend? | Notes |
|---|---|---|
UglifyJsPlugin |
Yes | Minimize code |
DedupePlugin |
Yes for v1 | Collapse identical code chunks to a single reference |
OccurrenceOrderPlugin |
Maybe for v1 | Reorder module and chunk ids by occurrence count |
DefinePlugin |
Maybe | Define constants for better optimization |
lodash-webpack-plugin |
Maybe | Optimize lodash |
Code splitting is a Webpack feature that enables a JS bundle within a single build to be split up and loaded on-demand in smaller parts. Code splitting is appropriate within a single page and build.
Webpack shared libraries are slightly different from code splitting scenarios in that the common dependencies are shareable across builds and require a two-part build. In a first step, a common shared bundle and manifest is created. Then, in a second step, entry points ingest the manifest and omit any libraries included in the shared bundle. Shared libraries are appropriate for better long term caching within a single app across deploys and across different projects / real HTML pages.
Scope hoisted bundles try to place bundle modules into a global bundle scope so as to reduce the overhead of function calls for each bundled module. The problem and scope hoisting solutions are discussed in detail in Nolan Lawson's 2016 article "The cost of small modules"
Tree shaking is a
transformation process for ES6 modules
whereby ESnext exports that are not used in a Webpack bundle can be isolated
during code bundling and removed entirely by Uglify dead code elimination.
The Webpack SourceMapDevToolPlugin creates source maps which allows a developer to view / debug developer-friendly source code instead of the optimized, mangled, and minified JS bundle of a frontend web app. Source maps should be enabled for both development and production.