Implement scopes on models and support interacting with them via ModelBuilder

src/orm/model/scope/ActiveScope.ts

@@ -0,0 +1,11 @@
+import {Scope} from './Scope'
+import {AbstractBuilder} from '../../builder/AbstractBuilder'
+
+/**
+ * A basic scope to limit results where `active` = true.
+ */
+export class ActiveScope extends Scope {
+    apply(query: AbstractBuilder<any>): void {
+        query.where('active', '=', true)
+    }
+}

src/orm/model/scope/Scope.ts

@@ -0,0 +1,18 @@
+import {Injectable, InjectionAware} from '../../../di'
+import {Awaitable} from '../../../util'
+import {AbstractBuilder} from '../../builder/AbstractBuilder'
+
+/**
+ * A closure that takes a query and applies some scope to it.
+ */
+export type ScopeClosure = (query: AbstractBuilder<any>) => Awaitable<void>
+
+/**
+ * Base class for scopes that can be applied to queries.
+ */
+@Injectable()
+export abstract class Scope extends InjectionAware {
+
+    abstract apply(query: AbstractBuilder<any>): Awaitable<void>
+
+}