geojson-transform-stream.js

var through2 = require('through2')
var byline = require('byline')

process.stdin
.pipe(byline.createStream())
.pipe(through2(function(chunk, enc, next){
  var data = JSON.parse(chunk.toString())
  
  this.push(toGeoJSON(data))

  next()
}))
.pipe(process.stdout)


function toGeoJSON (data) {
  if(data.type === 'node') {
    // return transformed node
  } else if(data.type === 'way') {
    // return transformed way
  } else if(data.type === 'relation') {
    // return transformed relation
  } else throw new Error('Unknown type detected: ' + data.type)
}