Implement scopes on models and support interacting with them via ModelBuilder

src/orm/model/Model.ts

@@ -1,5 +1,5 @@
 import {ModelKey, QueryRow, QuerySource} from '../types'
-import {Container, Inject, Instantiable, StaticClass} from '../../di'
+import {Container, Inject, Instantiable, isInstantiable, StaticClass} from '../../di'
 import {DatabaseService} from '../DatabaseService'
 import {ModelBuilder} from './ModelBuilder'
 import {getFieldsMeta, ModelField} from './Field'
@@ -21,6 +21,7 @@ import {Relation, RelationValue} from './relation/Relation'
 import {HasOne} from './relation/HasOne'
 import {HasMany} from './relation/HasMany'
 import {HasOneOrMany} from './relation/HasOneOrMany'
+import {Scope, ScopeClosure} from './scope/Scope'
 
 /**
  * Base for classes that are mapped to tables in a database.
@@ -87,6 +88,12 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
      */
     protected static masks: string[] = []
 
+    /**
+     * Relations that should be eager-loaded by default.
+     * @protected
+     */
+    protected with: (keyof T)[] = []
+
     /**
      * The original row fetched from the database.
      * @protected
@@ -105,6 +112,8 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
      */
     public relationCache: Collection<{ accessor: string | symbol, relation: Relation<T, any, any> }> = new Collection<{accessor: string | symbol; relation: Relation<T, any, any>}>()
 
+    protected scopes: Collection<{ accessor: string | Instantiable<Scope>, scope: ScopeClosure }> = new Collection<{accessor: string | Instantiable<Scope>; scope: ScopeClosure}>()
+
     /**
      * Get the table name for this model.
      */
@@ -165,6 +174,14 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
             builder.field(field.databaseKey)
         })
 
+        for ( const relation of this.prototype.with ) {
+            // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+            // @ts-ignore
+            builder.with(relation)
+        }
+
+        builder.withScopes(this.prototype.scopes)
+
         return builder
     }
 
@@ -317,6 +334,12 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
             builder.field(field.databaseKey)
         })
 
+        for ( const relation of this.with ) {
+            builder.with(relation)
+        }
+
+        builder.withScopes(this.scopes)
+
         return builder
     }
 
@@ -1013,7 +1036,7 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
      * @param name
      * @protected
      */
-    protected getRelation<T2 extends Model<T2>>(name: keyof this): Relation<T, T2, RelationValue<T2>> {
+    public getRelation<T2 extends Model<T2>>(name: keyof this): Relation<T, T2, RelationValue<T2>> {
         const relFn = this[name]
 
         if ( relFn instanceof Relation ) {
@@ -1029,4 +1052,60 @@ export abstract class Model<T extends Model<T>> extends AppClass implements Bus
 
         throw new TypeError(`Cannot get relation of name: ${name}. Method does not return a Relation.`)
     }
+
+    /**
+     * Register a scope on the model.
+     * @param scope
+     * @protected
+     */
+    protected scope(scope: Instantiable<Scope> | ScopeClosure): this {
+        if ( isInstantiable(scope) ) {
+            if ( !this.hasScope(scope) ) {
+                this.scopes.push({
+                    accessor: scope,
+                    scope: builder => (this.make<Scope>(scope)).apply(builder),
+                })
+            }
+        } else {
+            this.scopes.push({
+                accessor: uuid4(),
+                scope,
+            })
+        }
+
+        return this
+    }
+
+    /**
+     * Register a scope on the model with a specific name.
+     * @param name
+     * @param scope
+     * @protected
+     */
+    protected namedScope(name: string, scope: Instantiable<Scope> | ScopeClosure): this {
+        if ( isInstantiable(scope) ) {
+            if ( !this.hasScope(scope) ) {
+                this.scopes.push({
+                    accessor: name,
+                    scope: builder => (this.make<Scope>(scope)).apply(builder),
+                })
+            }
+        } else {
+            this.scopes.push({
+                accessor: name,
+                scope,
+            })
+        }
+
+        return this
+    }
+
+    /**
+     * Returns true if the current model has a scope with the given identifier.
+     * @param name
+     * @protected
+     */
+    protected hasScope(name: string | Instantiable<Scope>): boolean {
+        return Boolean(this.scopes.firstWhere('accessor', '=', name))
+    }
 }