gatsby-browser.js

// set flexsearch object as a global variable to make it available to language files
global.FlexSearch = require('flexsearch')

exports.onClientEntry = function(args, _ref) {
  // load json data into window variable
  fetch(`${__PATH_PREFIX__}/flexsearch_index.json`)
    .then(function(response) {
      return response.json()
    })
    .then(function(index) {
      Object.keys(index).forEach(lng => {
        Object.keys(index[lng].index).forEach(idx => {
          const index_ = index[lng].index[idx]

          // load language files if needed by stemmer or filter
          if (
            index_.attrs.stemmer !== undefined ||
            index_.attrs.filter !== undefined
          ) {
            try {
              if (lng === 'en') {
                require('./lang/en')
              } else if (lng === 'de') {
                require('./lang/en')
              } else {
                console.error(
                  'Language not supported by pre-defined stemmer or filter'
                )
              }
            } catch (e) {
              console.error(e)
            }
          }
          // rebuild the index
          const indexObj = new FlexSearch(index_.attrs)
          indexObj.import(index_.values)
          index_.values = indexObj
        })
      })
      // load index into window variable
      window.__FLEXSEARCH__ = index
    })
    .catch(function(e) {
      console.error('Failed fetch search index')
    })
}