feat(ability): stores ast property in Rule if conditionsMatcher…

… has `ast`

Relates to #350

packages/casl-ability/spec/ability.spec.js

@@ -546,6 +546,17 @@ describe('Ability', () => {
       it('does not allow to perform action on instance field if that instance matches conditions but field is not in specified list', () => {
         expect(ability).not.to.allow('read', myPost, 'id')
       })
+
+      it('has rules with `ast` property', () => {
+        const rule = ability.relevantRuleFor('read', 'Post');
+
+        expect(rule).to.have.property('ast').that.is.an('object');
+        expect(rule.ast).to.deep.equal({
+          field: 'author',
+          operator: 'eq',
+          value: rule.conditions.author
+        });
+      })
     })
   })
 

packages/casl-ability/src/Rule.ts

@@ -1,3 +1,4 @@
+import type { Condition } from '@ucast/mongo2js';
 import { wrapArray } from './utils';
 import {
   MatchConditions,
@@ -34,6 +35,7 @@ export class Rule<A extends Abilities, C> {
   public readonly conditions!: C | undefined;
   public readonly fields!: string[] | undefined;
   public readonly reason!: string | undefined;
+  public readonly ast?: Condition
 
   constructor(rule: RawRule<ToAbilityTypes<A>, C>, options: RuleOptions<A, C>) {
     validate(rule, options);
@@ -47,6 +49,7 @@ export class Rule<A extends Abilities, C> {
 
     if (this.conditions) {
       this._matchConditions = options.conditionsMatcher!(this.conditions);
+      this.ast = this._matchConditions.ast;
     }
 
     if (this.fields) {

packages/casl-ability/src/types.ts

@@ -1,3 +1,5 @@
+import type { Condition } from '@ucast/mongo2js';
+
 type Fn = (...args: any[]) => any;
 type AnyClass<ReturnType = any> = new (...args: any[]) => ReturnType;
 type AnyRecord = Record<PropertyKey, any>;
@@ -58,7 +60,10 @@ export type ForcedSubject<T> = { readonly __caslSubjectType__: T };
 type TaggedInterface<T extends string> = ForcedSubject<T> | { readonly kind: T };
 type TagName<T> = T extends TaggedInterface<infer U> ? U : never;
 
-export type MatchConditions<T extends object = AnyRecord> = (object: T) => boolean;
+export type MatchConditions<T extends object = AnyRecord> = {
+  (object: T): boolean
+  ast?: Condition
+};
 export type ConditionsMatcher<T> = (conditions: T) => MatchConditions;
 export type MatchField<T extends string> = (field: T) => boolean;
 export type FieldMatcher = <T extends string>(fields: T[]) => MatchField<T>;