add initial parsing

lib/import.js

@@ -1,4 +1,20 @@
+const makeStream = require('./stream');
+
 module.exports = importNmea;
 
-function importNmea() {
+/* global WritableStream */
+
+/**
+ * Parses ASCII stream containing NMEA messages into Furkot's trip
+ * @param {ReadableStream} from
+ */
+async function importNmea(from) {
+  const stream = makeStream();
+  let trip = [];
+
+  await from.pipeThrough(stream).pipeTo(new WritableStream({
+    write: packet => trip.push(packet)
+  }));
+
+  return trip;
 }

lib/stream.js

@@ -0,0 +1,49 @@
+const nmea = require("nmea-simple");
+
+module.exports = makeStream;
+
+/* global TransformStream */
+
+function makeStream() {
+  return new TransformStream(makeSource());
+}
+
+function makeSource() {
+  let prefix = '';
+  return {
+    transform,
+    flush
+  };
+
+  /**
+   * @param {String} chunk
+   * @param {TransformStreamDefaultController} controller
+   */
+  function transform(chunk, controller) {
+    const lines = chunk.split(/[\n\l]/);
+    if (prefix) {
+      lines[0] = prefix + lines[0];
+    }
+    prefix = lines.length > 1 ? lines.pop() : '';
+    for (const line of lines) {
+      if (line[0] === '$') {
+        const packet = nmea.parseNmeaSentence(line);
+        controller.enqueue(packet);
+      }
+    }
+  }
+
+  /**
+   * @param {TransformStreamDefaultController} controller
+   */
+  function flush(controller) {
+    if (prefix[0] === '$') {
+      const packet = nmea.parseNmeaSentence(prefix);
+      controller.enqueue(packet);
+    }
+  }
+}
+
+
+
+

package.json

@@ -14,7 +14,9 @@
     "nmea",
     "furkot"
   ],
-  "dependencies": {},
+  "dependencies": {
+    "nmea-simple": "^3.3.0"
+  },
   "devDependencies": {
     "@pirxpilot/jshint": "^3.0.1"
   },

test/fixtures/example.json

@@ -0,0 +1 @@
+[]