Split up connectionArgs

Author: taion

README.md

@@ -45,8 +45,12 @@ Helper functions are provided for both building the GraphQL types
 for connections and for implementing the `resolve` method for fields
 returning those types.
 
- - `connectionArgs` returns the arguments that fields should provide when
-they return a connection type.
+ - `connectionArgs` returns the arguments that fields should provide when they
+return a connection type that supports bidirectional pagination.
+ - `forwardConnectionArgs` returns the arguments that fields should provide
+when they return a connection type that only supports forward pagination.
+ - `backwardConnectionArgs` returns the arguments that fields should provide
+when they return a connection type that only supports backward pagination.
  - `connectionDefinitions` returns a `connectionType` and its associated
 `edgeType`, given a name and a node type.
  - `connectionFromArray` is a helper method that takes an array and the

src/connection/__tests__/connection.js

@@ -12,16 +12,18 @@ import {
   GraphQLObjectType,
   GraphQLSchema,
   GraphQLString,
-  graphql
+  graphql,
 } from 'graphql';
 
 import {
-  connectionFromArray
+  connectionFromArray,
 } from '../arrayconnection.js';
 
 import {
+  backwardConnectionArgs,
   connectionArgs,
-  connectionDefinitions
+  connectionDefinitions,
+  forwardConnectionArgs,
 } from '../connection.js';
 
 import { expect } from 'chai';
@@ -46,6 +48,16 @@ var userType = new GraphQLObjectType({
       args: connectionArgs,
       resolve: (user, args) => connectionFromArray(allUsers, args),
     },
+    friendsForward: {
+      type: friendConnection,
+      args: forwardConnectionArgs,
+      resolve: (user, args) => connectionFromArray(allUsers, args),
+    },
+    friendsBackward: {
+      type: friendConnection,
+      args: backwardConnectionArgs,
+      resolve: (user, args) => connectionFromArray(allUsers, args),
+    },
   }),
 });
 
@@ -121,4 +133,76 @@ describe('connectionDefinition()', () => {
     var result = await graphql(schema, query);
     expect(result).to.deep.equal({ data: expected });
   });
+
+  it('works with forwardConnectionArgs', async () => {
+    var query = `
+      query FriendsQuery {
+        user {
+          friendsForward(first: 2) {
+            edges {
+              node {
+                name
+              }
+            }
+          }
+        }
+      }
+    `;
+    var expected = {
+      user: {
+        friendsForward: {
+          edges: [
+            {
+              node: {
+                name: 'Dan'
+              }
+            },
+            {
+              node: {
+                name: 'Nick'
+              }
+            },
+          ]
+        }
+      }
+    };
+    var result = await graphql(schema, query);
+    expect(result).to.deep.equal({ data: expected });
+  });
+
+  it('works with backwardConnectionArgs', async () => {
+    var query = `
+      query FriendsQuery {
+        user {
+          friendsBackward(last: 2) {
+            edges {
+              node {
+                name
+              }
+            }
+          }
+        }
+      }
+    `;
+    var expected = {
+      user: {
+        friendsBackward: {
+          edges: [
+            {
+              node: {
+                name: 'Joe'
+              }
+            },
+            {
+              node: {
+                name: 'Tim'
+              }
+            },
+          ]
+        }
+      }
+    };
+    var result = await graphql(schema, query);
+    expect(result).to.deep.equal({ data: expected });
+  });
 });

src/connection/connection.js

@@ -23,24 +23,40 @@ import type {
 } from 'graphql';
 
 /**
- * Returns a GraphQLFieldConfigArgumentMap appropriate to include
- * on a field whose return type is a connection type.
+ * Returns a GraphQLFieldConfigArgumentMap appropriate to include on a field
+ * whose return type is a connection type with forward pagination.
  */
-export var connectionArgs: GraphQLFieldConfigArgumentMap = {
-  before: {
-    type: GraphQLString
-  },
+export var forwardConnectionArgs: GraphQLFieldConfigArgumentMap = {
   after: {
     type: GraphQLString
   },
   first: {
     type: GraphQLInt
   },
+};
+
+/**
+ * Returns a GraphQLFieldConfigArgumentMap appropriate to include on a field
+ * whose return type is a connection type with backward pagination.
+ */
+export var backwardConnectionArgs: GraphQLFieldConfigArgumentMap = {
+  before: {
+    type: GraphQLString
+  },
   last: {
     type: GraphQLInt
   },
 };
 
+/**
+ * Returns a GraphQLFieldConfigArgumentMap appropriate to include on a field
+ * whose return type is a connection type with bidirectional pagination.
+ */
+export var connectionArgs: GraphQLFieldConfigArgumentMap = {
+  ...forwardConnectionArgs,
+  ...backwardConnectionArgs,
+};
+
 type ConnectionConfig = {
   name: string,
   nodeType: GraphQLObjectType,