typesetting/pitfall/pdfkit/node_modules/JSONStream/index.js

var Parser = require('jsonparse')
  , Stream = require('stream').Stream
  , through = require('through')

/*

  the value of this.stack that creationix's jsonparse has is weird.

  it makes this code ugly, but his problem is way harder that mine,
  so i'll forgive him.

*/

exports.parse = function (path) {

  var parser = new Parser()
  var stream = through(function (chunk) {
    if('string' === typeof chunk) {
      if (process.browser) {
        var buf = new Array(chunk.length)
        for (var i = 0; i < chunk.length; i++) buf[i] = chunk.charCodeAt(i)
        chunk = new Int32Array(buf)
      } else {
        chunk = new Buffer(chunk)
      }
    }
    parser.write(chunk)
  },
  function (data) {
    if(data)
      stream.write(data)
    stream.queue(null)
  })

  if('string' === typeof path)
    path = path.split('.').map(function (e) {
      if (e === '*')
        return true
      else if (e === '') // '..'.split('.') returns an empty string
        return {recurse: true}
      else
        return e
    })


  var count = 0, _key
  if(!path || !path.length)
    path = null

  parser.onValue = function () {
    if (!this.root && this.stack.length == 1)
      stream.root = this.value

    if(! path) return

    var i = 0 // iterates on path
    var j  = 0 // iterates on stack
    while (i < path.length) {
      var key = path[i]
      var c
      j++

      if (key && !key.recurse) {
        c = (j === this.stack.length) ? this : this.stack[j]
        if (!c) return
        if (! check(key, c.key)) return
        i++
      } else {
        i++
        var nextKey = path[i]
        if (! nextKey) return
        while (true) {
          c = (j === this.stack.length) ? this : this.stack[j]
          if (!c) return
          if (check(nextKey, c.key)) { i++; break}
          j++
        }
      }
    }
    if (j !== this.stack.length) return

    count ++
    if(null != this.value[this.key])
      stream.queue(this.value[this.key])
    delete this.value[this.key]
  }
  parser._onToken = parser.onToken;

  parser.onToken = function (token, value) {
    parser._onToken(token, value);
    if (this.stack.length === 0) {
      if (stream.root) {
        if(!path)
          stream.queue(stream.root)
        stream.emit('root', stream.root, count)
        count = 0;
        stream.root = null;
      }
    }
  }

  parser.onError = function (err) {
    stream.emit('error', err)
  }


  return stream
}

function check (x, y) {
  if ('string' === typeof x)
    return y == x
  else if (x && 'function' === typeof x.exec)
    return x.exec(y)
  else if ('boolean' === typeof x)
    return x
  else if ('function' === typeof x)
    return x(y)
  return false
}

exports.stringify = function (op, sep, cl) {
  if (op === false){
    op = ''
    sep = '\n'
    cl = ''
  } else if (op == null) {

    op = '[\n'
    sep = '\n,\n'
    cl = '\n]\n'

  }

  //else, what ever you like

  var stream
    , first = true
    , anyData = false
  stream = through(function (data) {
    anyData = true
    var json = JSON.stringify(data)
    if(first) { first = false ; stream.queue(op + json)}
    else stream.queue(sep + json)
  },
  function (data) {
    if(!anyData)
      stream.queue(op)
    stream.queue(cl)
    stream.queue(null)
  })

  return stream
}

exports.stringifyObject = function (op, sep, cl) {
  if (op === false){
    op = ''
    sep = '\n'
    cl = ''
  } else if (op == null) {

    op = '{\n'
    sep = '\n,\n'
    cl = '\n}\n'

  }

  //else, what ever you like

  var stream = new Stream ()
    , first = true
    , anyData = false
  stream = through(function (data) {
    anyData = true
    var json = JSON.stringify(data[0]) + ':' + JSON.stringify(data[1])
    if(first) { first = false ; stream.queue(op + json)}
    else stream.queue(sep + json)
  }, 
  function (data) {
    if(!anyData) stream.queue(op)
    stream.queue(cl)

    stream.queue(null)
  })

  return stream
}