feat(action-policy): add whyCan and whyCannot methods (#59)

these methods returns all the statements that allow or not an action
roggervalf · Nov 8, 2021 · fef8e89 · fef8e89
1 parent 0bcb9ac
commit fef8e89
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diff --git a/src/ActionBasedPolicy.test.ts b/src/ActionBasedPolicy.test.ts
@@ -338,6 +338,21 @@ describe('ActionBasedPolicy Class', () => {
           context: { user: { id: 123 } }
         })
       ).toBe(true);
+      expect(
+        policy.whyCan({
+          action: 'getUser/123',
+          context: { user: { id: 123 } }
+        })
+      ).toMatchObject([
+        {
+          effect: 'allow',
+          action: [
+            'createProject',
+            'getUser/${user.id}',
+            'updateUser/${user.id}'
+          ]
+        }
+      ]);
       expect(
         policy.can({
           action: 'createProject'
@@ -371,6 +386,21 @@ describe('ActionBasedPolicy Class', () => {
           context: { user: { id: 123 } }
         })
       ).toBe(true);
+      expect(
+        policy.whyCannot({
+          action: 'getUser/123',
+          context: { user: { id: 123 } }
+        })
+      ).toMatchObject([
+        {
+          effect: 'deny',
+          action: [
+            'createProject',
+            'getUser/${user.id}',
+            'updateUser/${user.id}'
+          ]
+        }
+      ]);
       expect(
         policy.cannot({
           action: 'createProject'

diff --git a/src/ActionBasedPolicy.ts b/src/ActionBasedPolicy.ts
@@ -74,6 +74,23 @@ export class ActionBasedPolicy<T extends object> extends Policy<
     );
   }
 
+  whyCan(
+    this: ActionBasedPolicy<T>,
+    { action, context }: EvaluateActionBasedInterface<T>
+  ): ActionBasedType[] {
+    return this.allowStatements.reduce((statements, currentStatement) => {
+      const matches = currentStatement.matches({
+        action,
+        context: context || this.context,
+        conditionResolver: this.conditionResolver
+      });
+      if (matches) {
+        return [...statements, currentStatement.getStatement()];
+      }
+      return statements;
+    }, [] as ActionBasedType[]);
+  }
+
   cannot(
     this: ActionBasedPolicy<T>,
     { action, context }: EvaluateActionBasedInterface<T>
@@ -87,6 +104,23 @@ export class ActionBasedPolicy<T extends object> extends Policy<
     );
   }
 
+  whyCannot(
+    this: ActionBasedPolicy<T>,
+    { action, context }: EvaluateActionBasedInterface<T>
+  ): ActionBasedType[] {
+    return this.denyStatements.reduce((statements, currentStatement) => {
+      const matches = currentStatement.matches({
+        action,
+        context: context || this.context,
+        conditionResolver: this.conditionResolver
+      });
+      if (matches) {
+        return [...statements, currentStatement.getStatement()];
+      }
+      return statements;
+    }, [] as ActionBasedType[]);
+  }
+
   generateProxy<U extends object>(
     this: ActionBasedPolicy<T>,
     obj: U,