Newline Proliferating Maniac

    peek-stream

    1.1.3 • Public • Published

    peek-stream

    Transform stream that lets you peek the first line before deciding how to parse it

    npm install peek-stream
    

    build status dat

    Usage

    var peek = require('peek-stream')
    var ldjson = require('ldjson-stream')
    var csv = require('csv-parser')
     
    var isCSV = function(data) {
      return data.toString().indexOf(',') > -1
    }
     
    var isJSON = function(data) {
      try {
        JSON.parse(data)
        return true
      } catch (err) {
        return false
      }
    }
     
    // call parser to create a new parser
    var parser = function() {
      return peek(function(data, swap) {
        // maybe it is JSON?
        if (isJSON(data)) return swap(null, ldjson())
     
        // maybe it is CSV?
        if (isCSV(data)) return swap(null, csv())
     
        // we do not know - bail
        swap(new Error('No parser available'))
      })
    }

    The above parser will be able to parse both line delimited JSON and CSV

    var parse = parser()
     
    parse.write('{"hello":"world"}\n{"hello":"another"}\n')
    parse.on('data', function(data) {
      console.log(data) // prints {hello:'world'} and {hello:'another'}
    })

    Or

    var parse = parser()
     
    parse.write('test,header\nvalue-1,value-2\n')
    parse.on('data', function(data) {
      console.log(data) // prints {test:'value-1', header:'value-2'}
    })

    Per default data is the first line (or the first 65535 bytes if no newline is found). To change the max buffer pass an options map to the constructor

    var parse = peek({
      maxBuffer: 10000
    }, function(data, swap) {
      ...
    })

    If you want to emit an error if no newline is found set strict: true as well.

    License

    MIT

    Install

    npm i peek-stream

    DownloadsWeekly Downloads

    264,989

    Version

    1.1.3

    License

    MIT

    Unpacked Size

    8.16 kB

    Total Files

    7

    Last publish

    Collaborators

    • mafintosh