search through a gzip file line by line on the client

search.js

  function search(keyword) {
    let chunks = 0;

    isSearching = true;
    return fetch(`${__webpack_public_path__}/placeNames.tsv.gz`).then(async res => {
      const blob = await res.blob();
      const ds = new DecompressionStream('gzip');
      const reader = blob.stream().pipeThrough(ds).pipeThrough(new TextDecoderStream()).getReader();
      let partialLine = '';
      const found = [];
      while (true) {
        const { done, value } = await reader.read();
        if (searchTerm !== keyword) {
          console.log('aborting search', keyword);
        }
        chunks++;
        if (done) break;
        const theseLines = partialLine + value;
        const split = theseLines.split('\n');
        partialLine = split.pop();
        found.push(
          ...split
            .filter(line => line.split('\t')[0].toLowerCase().includes(keyword.toLowerCase()))
            .map(line => {
              const [name, latitude, longitude, countrycode, population] = line.split('\t');
              return {
                id: name + population + latitude + longitude,
                name,
                latitude,
                longitude,
                countrycode,
                population: Number(population)
              };
            })
        );
      }
      isSearching = false;
      return found;
    });
  }