Add bindForClient utility function

Author: jbmusso

README.md

@@ -249,6 +249,28 @@ client.stream('g.v(vid)', { vid: 1 }, { args: { language: 'nashorn' }})
   .pipe(/* ... */);
 ```
 
+### Gremlin.bindForClient()
+
+Given a map of functions returning query `Object`s (`{ gremlin, bindings }`), returns a map of function promising execution of these queries with the given Gremlin client.
+
+This function is especially useful when used with [gremlin-loader](https://github.com/jbmusso/gremlin-loader), a Webpack loader which imports functions from `.groovy` files as `Object<String, Functions>` where each functions returns query `Object`s that need to be executed with a client.
+
+```javascript
+import { bindForClient, createClient } from 'gremlin';
+
+// A function returning a Gremlin query object { gremlin, bindings }
+const getByName = (name) => ({
+  gremlin: 'g.V().has("name", name)',
+  bindings: { name }
+});
+
+const client = createClient();
+const queries = bindForClient(client, { getByName });
+
+// Then, within an async function:
+const users = await queries.getByName('Alice');
+```
+
 ### Using Gremlin-JavaScript syntax with Nashorn
 
 Please see [/docs/UsingNashorn.md](Using Nashorn).

src/index.js

@@ -1,6 +1,8 @@
-import GremlinClient from './GremlinClient';
+import _ from 'lodash';
 import template from 'gremlin-template-string';
 
+import GremlinClient from './GremlinClient';
+
 
 export function createClient(port, host, options) {
   if (typeof port === 'object') {
@@ -16,8 +18,15 @@ export function createClient(port, host, options) {
   return new GremlinClient(port, host, options);
 };
 
-export const makeTemplateTag = (client) => (...gremlinChunks) => {
-  const query = template(...gremlinChunks);
+
+/**
+ * Given a query object, returns a Promise of executing that query with a
+ * given client.
+ * @param  {GremlinClient} client Gremlin client to execute queries with
+ * @param  {Object} query  A query Object { gremlin: String, bindings: Object }
+ * @return {Promise} Promise of execution of the query
+ */
+const makePromise = (client, query) => {
   const promise = new Promise((resolve, reject) =>
     client.execute(query, (err, results) =>
       err ? reject(err) : resolve(results)
@@ -29,7 +38,25 @@ export const makeTemplateTag = (client) => (...gremlinChunks) => {
   return promise;
 }
 
+export const makeTemplateTag = (client) =>
+  (...gremlinChunks) => makePromise(client, template(...gremlinChunks));
+
+/**
+ * Given a map of functions returning query objects, returns a map
+ * of function promising execution of these queries with the given Gremlin
+ * client.
+ *
+ * @param  {GremlinClient} client Gremlin client to execute queries with
+ * @param  {Object<String, Function<Object>>} functions
+ * @return {Object<String, Function<Promise<Results>>>}
+ */
+export const bindForClient = (client, functions) => _(functions)
+  .mapValues((fn) => (...args) => makePromise(client, fn(...args)))
+  .value();
+
+
 export default {
   createClient,
-  makeTemplateTag
+  makeTemplateTag,
+  bindForClient
 }

test/bindForClient.js

@@ -0,0 +1,25 @@
+import { createClient, bindForClient } from '../';
+import { assert } from 'chai';
+
+
+const getByName = (name) => ({
+  gremlin: 'g.V().has("name", name)',
+  bindings: {
+    name
+  }
+});
+
+describe('.bindForClient()', () => {
+  it('should return a map of bound functions', async (done) => {
+    const client = createClient();
+    const queries = bindForClient(client, { getByName });
+    assert.isFunction(queries.getByName);
+
+    const promise = queries.getByName('marko');
+    assert.property(promise, 'query');
+
+    const result = await promise;
+    result.length.should.equal(1)
+    done();
+  });
+});