Add support for jstype annotation (#104)

* Add support for jstype annotation

Required an upgrade to google-protobuf 3.6.1, otherwise very straight forward.

Fixes #17

* Add test coverage for all support field types

README.md

@@ -172,3 +172,12 @@ client.getUser(req, (err, user) => { /* ... */ });
 For a sample of the generated protos and service definitions, see [examples](https://github.com/improbable-eng/ts-protoc-gen/tree/master/examples).
 
 To generate the examples from protos, please run `./generate.sh`
+
+## Gotchas
+By default the google-protobuf library will use the JavaScript number type to store 64bit float and integer values; this can lead to overflow problems as you exceed JavaScript's `Number.MAX_VALUE`. To work around this, you should consider using the `jstype` annotation on any 64bit fields, ie:
+
+```proto
+message Example {
+  uint64 bigInt = 1 [jstype = JS_STRING];
+}
+```

package.json

@@ -29,7 +29,7 @@
   "author": "Improbable",
   "license": "Apache-2.0",
   "dependencies": {
-    "google-protobuf": "^3.5.0"
+    "google-protobuf": "^3.6.1"
   },
   "devDependencies": {
     "@types/chai": "^3.5.2",

proto/examplecom/annotations.proto

@@ -0,0 +1,11 @@
+syntax = "proto3";
+
+package examplecom;
+
+message AnnotatedMessage {
+  uint64 myUnit64 = 1 [jstype = JS_STRING];
+  int64 myInt64 = 2 [jstype = JS_STRING];
+  fixed64 myFixed64 = 3 [jstype = JS_STRING];
+  sint64 mySint64 = 4 [jstype = JS_STRING];
+  sfixed64 mySfixed64 = 5 [jstype = JS_STRING];
+}