demo-stream-gzipped-json-files.js

const zlib = require('zlib');
const unzip = zlib.createUnzip();
const fs = require('fs');
var geojsonStream = require('geojson-stream');

function mergeFeatureCollectionStream (inputs) {

    var out = geojsonStream.stringify();
    inputs.map(async (file) => {
        fs.createReadStream(file)
            .pipe(unzip)
            .pipe(geojsonStream.parse())
            .pipe(out)
    });
    return out;
}

var mergedStream = mergeFeatureCollectionStream([
  'cadastre-38002-parcelles.json.gz',
  'cadastre-38006-parcelles.json.gz'
])

mergedStream.pipe(process.stdout);

demo-stream-json-files.js

const fs = require('fs');
var geojsonStream = require('geojson-stream');


function mergeFeatureCollectionStream (inputs) {
    var out = geojsonStream.stringify();
    inputs.forEach(function(file) {
        fs.createReadStream(file)
            .pipe(geojsonStream.parse())
            .pipe(out);
    });
    return out;
}

var mergedStream = mergeFeatureCollectionStream([
  'cadastre-38002-parcelles.json'
  ,'cadastre-38006-parcelles.json'
])

mergedStream.pipe(process.stdout);

prepare-env-and-data.sh

npm i geojson-stream
wget "https://cadastre.data.gouv.fr/data/etalab-cadastre/2023-01-01/geojson/communes/38/38002/cadastre-38002-parcelles.json.gz"
wget "https://cadastre.data.gouv.fr/data/etalab-cadastre/2023-01-01/geojson/communes/38/38006/cadastre-38006-parcelles.json.gz";
gzip -k -f -d cadastre-38002-parcelles.json.gz
gzip -k -f -d cadastre-38006-parcelles.json.gz