Create Node Streams Transformer interface and add command a command l…

…ine tool

bin/parse-nmea

@@ -0,0 +1,10 @@
+#!/usr/bin/env node
+
+var Liner = require('../liner.js');
+
+process.stdin.resume();
+process.stdin.setEncoding('utf8');
+
+
+//process.stdin.pipe(new Liner()).pipe(require('../nmea.js').createDefaultTransformer()).pipe(process.stdout);
+process.stdin.pipe(new Liner()).pipe(require('../nmea.js').createDefaultTransformer()).pipe(require('JSONStream').stringify(false)).pipe(process.stdout);;

helpers.js

@@ -233,7 +233,7 @@ exports.encodeFixed = function(v, f) {
 };
 
 // =========================================
-// field parsers
+// field traditionalDecoders
 // =========================================
 
 // separate number and units

liner.js

@@ -0,0 +1,49 @@
+var Transform = require('stream').Transform;
+
+function Liner() {
+  Transform.call(this, { objectMode: true });
+}
+
+Liner.prototype = {
+  _transform: function (chunk, encoding, done) {
+    var data = chunk.toString()
+    if (this._lastLineData) data = this._lastLineData + data
+
+    var lines = data.split('\n')
+    this._lastLineData = lines.splice(lines.length - 1, 1)[0]
+
+    lines.forEach(this.push.bind(this))
+    done()
+  },
+  _flush: function (done) {
+    if (this._lastLineData) this.push(this._lastLineData)
+    this._lastLineData = null
+    done()
+  }
+}
+
+extend(Transform, Liner);
+
+function extend(base, sub) {
+  // Avoid instantiating the base class just to setup inheritance
+  // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/create
+  // for a polyfill
+  // Also, do a recursive merge of two prototypes, so we don't overwrite
+  // the existing prototype, but still maintain the inheritance chain
+  // Thanks to @ccnokes
+  var origProto = sub.prototype;
+  sub.prototype = Object.create(base.prototype);
+  for (var key in origProto) {
+    sub.prototype[key] = origProto[key];
+  }
+  // Remember the constructor property was set wrong, let's fix it
+  sub.prototype.constructor = sub;
+  // In ECMAScript5+ (all modern browsers), you can make the constructor property
+  // non-enumerable if you define it like this instead
+  Object.defineProperty(sub.prototype, 'constructor', {
+    enumerable: false,
+    value: sub
+  });
+}
+
+module.exports = Liner;

nmea.js

@@ -24,7 +24,7 @@ var validLine = function(line) {
     return checkVal == parseInt(parts[1], 16);
 };
 
-exports.parsers = {
+exports.traditionalDecoders = {
   GGA: GGA.decode,
   RMC: RMC.decode,
   APB: APB.decode,
@@ -80,3 +80,13 @@ exports.encode = function(talker, msg) {
     throw Error("No encoder for type:" + msg.type);
   }
 }
+
+exports.createDefaultTransformer = function (options) {
+  var stream = require('through')(function (data) {
+    try {
+      stream.queue(exports.parse(data));
+    } catch (e) {
+    }
+  });
+  return stream;
+};

package.json

@@ -10,5 +10,9 @@
         "should": "~2.0.2",
       "mocha": "1.13",
       "line-reader": "0.2"
+    },
+    "dependencies" : {
+      "through": ">=2.2.7 <3",
+      "JSONStream" : "0.7"
     }
 }