geojson-stream

Stream features into and out of GeoJSON objects and Feature Collections. Little more than JSONStream with pre-filled settings.

usage

npm install --save geojson-stream

api

geojsonStream.stringify()

Returns a transform stream that accepts GeoJSON Feature objects and emits a stringified FeatureCollection.

geojsonStream.parse(mapFunc)

Returns a transform stream that accepts a GeoJSON FeatureCollection as a stream and emits Feature objects.

mapFunc(feature, index) is an optional function which takes a Feature, and its zero-based index in the FeatureCollection and returns either a Feature, or null/undefined if the feature should be omitted from output.

example

const geojsonStream = require('geojson-stream');
const fs = require('fs');
const out = fs.createWriteStream('buildings-with-id.geojson');
fs
    .createReadStream(`buildings.geojson`)
    .pipe(geojsonStream.parse((building, index) => {
        if (building.geometry.coordinates === null) {
            return null;
        }
        building.id = index;
        return building;
    }))
    .pipe(geojsonStream.stringify())
    .pipe(out);