Function prefetchData

packages/react-static/src/browser/index.js:278–344

(path, { priority } = {})

}

export async function prefetchData(path, { priority } = {}) {
  // Get route info so we can check if path has any data
  const routeInfo = await getRouteInfo(path, { priority })

  // Not a static route? Bail out.
  if (!routeInfo) {
    return
  }

  // Defer to the cache first. In dev mode, this should already be available from
  // the call to getRouteInfo
  if (routeInfo.sharedData) {
    return getFullRouteData(routeInfo)
  }

  // Request and build the props one by one
  routeInfo.sharedData = {}

  // Request the template and loop over the routeInfo.sharedHashesByProp, requesting each prop
  await Promise.all(
    Object.keys(routeInfo.sharedHashesByProp).map(async key => {
      const hash = routeInfo.sharedHashesByProp[key]

      // Check the sharedDataByHash first
      if (!sharedDataByHash[hash]) {
        // Reuse request for duplicate inflight requests
        try {
          const staticDataPath = pathJoin(
            process.env.REACT_STATIC_ASSETS_PATH,
            `staticData/${hash}.json`
          )
          const absoluteStaticDataPath = makePathAbsolute(staticDataPath)

          // If priority, get it immediately
          if (priority) {
            const { data: prop } = await axios.get(absoluteStaticDataPath)
            sharedDataByHash[hash] = prop
          } else {
            // Non priority, share inflight requests and use pool
            if (!inflightPropHashes[hash]) {
              inflightPropHashes[hash] = requestPool.add(() =>
                axios.get(absoluteStaticDataPath)
              )
            }
            const { data: prop } = await inflightPropHashes[hash]
            // Place it in the cache
            sharedDataByHash[hash] = prop
          }
        } catch (err) {
          console.log(
            'Error: There was an error retrieving a prop for this route! hashID:',
            hash
          )
          console.error(err)
        }
        if (!priority) {
          delete inflightPropHashes[hash]
        }