feat(many-to-many): Adds many to many decorators (#26)

src/decorators/ManyToMany.ts

@@ -0,0 +1,13 @@
+import { Field } from 'type-graphql';
+import { ManyToMany as TypeORMManyToMany } from 'typeorm';
+
+import { composeMethodDecorators, MethodDecoratorFactory } from '../utils';
+
+export function ManyToMany(parentType: any, joinFunc: any, options: any = {}): any {
+  const factories = [
+    Field(() => [parentType()], { nullable: true, ...options }) as MethodDecoratorFactory,
+    TypeORMManyToMany(parentType, joinFunc, options) as MethodDecoratorFactory
+  ];
+
+  return composeMethodDecorators(...factories);
+}

src/decorators/ManyToManyJoin.ts

@@ -0,0 +1,17 @@
+import { Field } from 'type-graphql';
+import { JoinTable, ManyToMany as TypeORMManyToMany } from 'typeorm';
+
+import { composeMethodDecorators, MethodDecoratorFactory } from '../utils';
+
+// Note: for many to many relationships, you need to set one item as the "JoinTable"
+// therefore, we have 2 separate decorators.  Just make sure to add one to one table and
+// One to the other in the relationship
+export function ManyToManyJoin(parentType: any, joinFunc: any, options: any = {}): any {
+  const factories = [
+    JoinTable() as MethodDecoratorFactory,
+    Field(() => [parentType()], { nullable: true, ...options }) as MethodDecoratorFactory,
+    TypeORMManyToMany(parentType, joinFunc, options) as MethodDecoratorFactory
+  ];
+
+  return composeMethodDecorators(...factories);
+}

src/decorators/index.ts

@@ -1,5 +1,7 @@
 export * from './EmailField';
 export * from './EnumField';
+export * from './ManyToMany';
+export * from './ManyToManyJoin';
 export * from './Model';
 export * from './StringField';
 export * from './ForeignKeyField';