Dependency reduction and modernization

[1000TurquoisePogs]

explorer-uss

Modernize build toolchain and remove dead dependencies

TypeScript / Build

• Migrated from Babel to TypeScript: replaced babel-loader + @babel/\* with ts-loader; added tsconfig.json
• Renamed all source files from .js/.jsx to .ts/.tsx
• Added explicit type annotations throughout source: boolean, number, and string parameters/variables

Linting

• Replaced eslint-config-airbnb stack with @typescript-eslint/eslint-plugin + @typescript-eslint/parser

Testing

• Replaced nyc with c8 for coverage
• Removed sinon: replaced with a lightweight manual stub helper
• Removed rewire: exported previously-private constants and functions directly so tests access them without module patching

Dependencies removed

• babel-loader, @babel/core, @babel/preset-env, @babel/preset-react, @babel/preset-typescript
• eslint-config-airbnb, eslint-plugin-import, eslint-plugin-jsx-a11y, eslint-plugin-react
• rewire, sinon, @types/sinon, redux-logger, nyc, file-loader

Dependency upgrades

• webpack 5.94 → 5.107.1, webpack-cli 5.1.4 → 7.0.2, webpack-dev-server 4.x → 5.2.4
• css-loader 7.1.2 → 7.1.4, terser-webpack-plugin 5.3.10 → 5.6.0, html-webpack-plugin → 5.6.7
• url-loader replaced by webpack 5 built-in asset/resource module

CI / Workflows

• All workflow files updated to Node 22 and actions/setup-node@v4 (previously node 16 in code_scan, node 18 in build_test)

[sonarqubecloud]

Quality Gate failed

Failed conditions
63.1% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud