feat: allow strings as query input

Closes #4

README.md

@@ -12,7 +12,6 @@ import "./styles.css";
 import graphql from "reactive-graphql";
 
 import { makeExecutableSchema } from "graphql-tools";
-import gql from "graphql-tag";
 import { from, interval, of } from "rxjs";
 import { map, merge, scan, combineLatest } from "rxjs/operators";
 import { componentFromStream } from "@dcos/data-service";
@@ -66,7 +65,7 @@ const schema = makeExecutableSchema({
   }
 });
 
-const query = gql`
+const query = `
   query {
     posts {
       title
@@ -111,7 +110,7 @@ ReactDOM.render(<App />, rootElement);
 
 ## API
 
-The first argument you pass into `reactive-graphql` is an executable schema, the second one a parsed GraphQL query. You can pass in the root context as an object as a third parameter. The variables can be passed as 4th parameter.
+The first argument you pass into `reactive-graphql` is an executable schema, the second one a GraphQL query, either parsed or as string. You can pass in the root context as an object as a third parameter. The variables can be passed as 4th parameter.
 
 The implementation will always return an Observable.
 If any of the resolvers returns an error the implementation will emit the error on the stream.

src/__tests__/graphqlObservable-test.ts

@@ -201,6 +201,26 @@ describe("graphqlObservable", function() {
       m.expect(result.pipe(take(1))).toBeObservable(expected);
     });
 
+    itMarbles("solves listing all fields with string query", function(m) {
+      const query = `
+        query {
+          launched {
+            name
+          }
+        }
+      `;
+
+      const expectedData = [{ name: "discovery" }];
+      const dataSource = of(expectedData);
+      const expected = m.cold("(a|)", {
+        a: { data: { launched: expectedData } }
+      });
+
+      const result = graphql(schema, query, { query: dataSource });
+
+      m.expect(result.pipe(take(1))).toBeObservable(expected);
+    });
+
     itMarbles("filters by variable argument", function(m) {
       const query = gql`
         query {

src/reactive-graphql.ts

@@ -19,7 +19,8 @@ import {
   ArgumentNode,
   isScalarType,
   isEnumType,
-  isObjectType
+  isObjectType,
+  parse
 } from "graphql";
 
 // WARNING: This is NOT a spec complete graphql implementation
@@ -67,12 +68,24 @@ function isFieldWithResolver(
 
 export default function graphql<T = object>(
   schema: Schema,
-  doc: DocumentNode,
+  query: string | DocumentNode,
   context: object = {},
   variables: object = {}
-): Observable<{ data: T }> {
+): Observable<{ data?: T; errors?: string[] }> {
+  // Parse
+  let doc;
+  if (typeof query === "string") {
+    try {
+      doc = parse(query);
+    } catch (syntaxError) {
+      return of({ errors: [syntaxError] });
+    }
+  } else {
+    doc = query;
+  }
+
   if (doc.definitions.length !== 1) {
-    return throwObservable("document root must have a single definition");
+    return throwObservable("query must have a single definition as root");
   }
 
   if (!schema._typeMap) {