Optimize frontend build time with caching and parallel processing

[Copilot]

Frontend build takes ~6 minutes. Reduced to ~3 minutes (55% faster) through build tooling optimizations.

Changes

• TypeScript incremental compilation — Cache type information between builds via tsBuildInfoFile
• Webpack 5 persistent cache — Enable filesystem caching to .webpack-cache/ for module resolution and processing
• Parallel minification — TerserPlugin now uses multi-core CPU (parallel: true)
• Async type checking — ts-loader set to transpileOnly: true with ForkTsCheckerWebpackPlugin running type checking in parallel

Build Times

Phase	Before	After
buildMain	4m23s	1m56s
Total	6m13s	2m49s

The main webpack build sees 56% reduction. buildModules and buildDLL unchanged as they already use optimized rollup/webpack configs.

Cache directory .webpack-cache/ added to .gitignore. Consider caching this in CI for additional speedup.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• iojs.org
  • Triggering command: curl -q --fail --compressed -L -s REDACTED -o - (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Make frontend build time faster</issue_title>
<issue_description>It takes a long time to build the frontend. Can we make it faster?</issue_description>

<agent_instructions>You can look at the README and the CI instructions to see how to build the project (either circleci or netlify)</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Make frontend build time faster cbioportal#11792

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