Function prerender

packages/start-plugin-core/src/prerender.ts:11–284

({
  startConfig,
  builder,
}: {
  startConfig: TanStackStartOutputConfig
  builder: ViteBuilder
})

import type { Page, TanStackStartOutputConfig } from './schema'

export async function prerender({
  startConfig,
  builder,
}: {
  startConfig: TanStackStartOutputConfig
  builder: ViteBuilder
}) {
  const logger = createLogger('prerender')
  logger.info('Prerendering pages...')

  // If prerender is enabled
  if (startConfig.prerender?.enabled) {
    // default to root page if no pages are defined
    let pages = startConfig.pages.length ? startConfig.pages : [{ path: '/' }]

    if (startConfig.prerender.autoStaticPathsDiscovery ?? true) {
      // merge discovered static pages with user-defined pages
      const pagesMap = new Map(pages.map((item) => [item.path, item]))
      const discoveredPages = globalThis.TSS_PRERENDABLE_PATHS || []

      for (const page of discoveredPages) {
        if (!pagesMap.has(page.path)) {
          pagesMap.set(page.path, page)
        }
      }

      pages = Array.from(pagesMap.values())
    }

    startConfig.pages = pages
  }

  const routerBasePath = joinURL('/', startConfig.router.basepath ?? '')
  const routerBaseUrl = new URL(routerBasePath, 'http://localhost')

  // Enforce that prerender page paths are relative/path-based (no protocol/host)
  startConfig.pages = validateAndNormalizePrerenderPages(
    startConfig.pages,
    routerBaseUrl,
  )

  const serverEnv = builder.environments[VITE_ENVIRONMENT_NAMES.server]

  if (!serverEnv) {
    throw new Error(
      `Vite's "${VITE_ENVIRONMENT_NAMES.server}" environment not found`,
    )
  }

  const clientEnv = builder.environments[VITE_ENVIRONMENT_NAMES.client]
  if (!clientEnv) {
    throw new Error(
      `Vite's "${VITE_ENVIRONMENT_NAMES.client}" environment not found`,
    )
  }

  const outputDir = clientEnv.config.build.outDir