Merge pull request #2 from pabloem/core-api

sketching the core API for JS SDK

sdks/node-ts/src/apache_beam/core.ts

@@ -0,0 +1,39 @@
+class PValue {
+    constructor() {
+    }
+
+    apply(transform: PTransform): PValue {
+        return transform.expand(this);
+    }
+
+    map(callable): PValue {
+        return this.apply(new ParDo(callable));
+    }
+
+}
+
+class Pipeline extends PValue {
+
+}
+
+class PCollection extends PValue {
+
+}
+
+class PTransform {
+    expand(input: PValue): PValue {
+        throw new Error('Method expand has not been implemented.');
+    }
+}
+
+class ParDo extends PTransform {
+    private doFn;
+    constructor(callableOrDoFn) {
+        super()
+        this.doFn = callableOrDoFn;
+    }
+}
+
+class DoFn {
+
+}