feat: refactors extra subpackage in casl/ability and adds AccessibleFields helper class (#883)

Author: stalniy

packages/casl-ability/extra.d.ts

@@ -1 +1 @@
-export * from './extra/extra';
+export * from './dist/types/extra';

packages/casl-ability/extra/extra.d.ts

@@ -1,7 +1,7 @@
 {
   "name": "@casl/ability/extra",
-  "typings": "./extra.d.ts",
+  "typings": "../dist/types/extra/index.d.ts",
   "main": "../dist/umd/extra.js",
   "module": "../dist/es5m/extra.js",
-  "es2015": "../dist/es6/extra.js"
+  "es2015": "../dist/es6c/extra.js"
 }

packages/casl-ability/extra/package.json

@@ -15,9 +15,9 @@
       "require": "./dist/es6c/index.js"
     },
     "./extra": {
-      "types": "./dist/types/extra.d.ts",
-      "import": "./dist/es6m/extra.mjs",
-      "require": "./dist/es6c/extra.js"
+      "types": "./dist/types/extra/index.d.ts",
+      "import": "./dist/es6m/extra/index.mjs",
+      "require": "./dist/es6c/extra/index.js"
     }
   },
   "sideEffects": false,
@@ -32,16 +32,14 @@
   },
   "scripts": {
     "build.core": "dx rollup -n casl -g @ucast/mongo2js:ucast.mongo2js",
-    "build.extra": "dx rollup -i src/extra.ts -n casl.extra -g @ucast/mongo2js:ucast.mongo2js",
-    "build.types": "dx tsc && cp index.metadata.json dist/types",
+    "build.extra": "dx rollup -i src/extra/index.ts -n casl.extra -g @ucast/mongo2js:ucast.mongo2js",
+    "build.types": "dx tsc",
     "prebuild": "rm -rf dist/*",
     "build": "npm run build.types && npm run build.core && npm run build.extra",
     "lint": "dx eslint src/ spec/",
     "test": "dx jest",
     "prerelease": "npm run lint && npm test && NODE_ENV=production npm run build",
-    "release": "dx semantic-release",
-    "preb": "echo 'pre'",
-    "b": "echo 123"
+    "release": "dx semantic-release"
   },
   "keywords": [
     "permissions",

packages/casl-ability/index.metadata.json

@@ -0,0 +1,5 @@
+export * from './packRules';
+export * from './permittedFieldsOf';
+export * from './rulesToFields';
+export * from './rulesToQuery';
+export * from './packRules';

packages/casl-ability/package.json

@@ -0,0 +1,61 @@
+
+import { RawRule } from '../RawRule';
+import { SubjectType } from '../types';
+import { wrapArray } from '../utils';
+
+const joinIfArray = (value: string | string[]) => Array.isArray(value) ? value.join(',') : value;
+
+export type PackRule<T extends RawRule<any, any>> =
+  [string, string] |
+  [string, string, T['conditions']] |
+  [string, string, T['conditions'] | 0, 1] |
+  [string, string, T['conditions'] | 0, 1 | 0, string] |
+  [string, string, T['conditions'] | 0, 1 | 0, string | 0, string];
+
+export type PackSubjectType<T extends SubjectType> = (type: T) => string;
+
+export function packRules<T extends RawRule<any, any>>(
+  rules: T[],
+  packSubject?: PackSubjectType<T['subject']>
+): PackRule<T>[] {
+  return rules.map((rule) => { // eslint-disable-line
+    const packedRule: PackRule<T> = [
+      joinIfArray((rule as any).action || (rule as any).actions),
+      typeof packSubject === 'function'
+        ? wrapArray(rule.subject).map(packSubject).join(',')
+        : joinIfArray(rule.subject),
+      rule.conditions || 0,
+      rule.inverted ? 1 : 0,
+      rule.fields ? joinIfArray(rule.fields) : 0,
+      rule.reason || ''
+    ];
+
+    while (packedRule.length > 0 && !packedRule[packedRule.length - 1]) packedRule.pop();
+
+    return packedRule;
+  });
+}
+
+export type UnpackSubjectType<T extends SubjectType> = (type: string) => T;
+
+export function unpackRules<T extends RawRule<any, any>>(
+  rules: PackRule<T>[],
+  unpackSubject?: UnpackSubjectType<T['subject']>
+): T[] {
+  return rules.map(([action, subject, conditions, inverted, fields, reason]) => {
+    const subjects = subject.split(',');
+    const rule = {
+      inverted: !!inverted,
+      action: action.split(','),
+      subject: typeof unpackSubject === 'function'
+        ? subjects.map(unpackSubject)
+        : subjects
+    } as T;
+
+    if (conditions) rule.conditions = conditions;
+    if (fields) rule.fields = fields.split(',');
+    if (reason) rule.reason = reason;
+
+    return rule;
+  });
+}

packages/casl-ability/src/extra.ts

@@ -0,0 +1,69 @@
+import { AnyAbility } from '../PureAbility';
+import { Rule } from '../Rule';
+import { RuleOf } from '../RuleIndex';
+import { Subject, SubjectType } from '../types';
+
+export type GetRuleFields<R extends Rule<any, any>> = (rule: R) => string[];
+
+export interface PermittedFieldsOptions<T extends AnyAbility> {
+  fieldsFrom: GetRuleFields<RuleOf<T>>
+}
+
+export function permittedFieldsOf<T extends AnyAbility>(
+  ability: T,
+  action: Parameters<T['can']>[0],
+  subject: Parameters<T['can']>[1],
+  options: PermittedFieldsOptions<T>
+): string[] {
+  const subjectType = ability.detectSubjectType(subject);
+  const rules = ability.possibleRulesFor(action, subjectType);
+  const uniqueFields = new Set<string>();
+  const deleteItem = uniqueFields.delete.bind(uniqueFields);
+  const addItem = uniqueFields.add.bind(uniqueFields);
+  let i = rules.length;
+
+  while (i--) {
+    const rule = rules[i];
+    if (rule.matchesConditions(subject)) {
+      const toggle = rule.inverted ? deleteItem : addItem;
+      options.fieldsFrom(rule).forEach(toggle);
+    }
+  }
+
+  return Array.from(uniqueFields);
+}
+
+export type GetSubjectTypeAllFieldsExtractor = (subjectType: SubjectType) => string[];
+
+/**
+ * Helper class to make custom `accessibleFieldsBy` helper function
+ */
+export class AccessibleFields<T extends Subject> {
+  constructor(
+    private readonly _ability: AnyAbility,
+    private readonly _action: string,
+    private readonly _getAllFields: GetSubjectTypeAllFieldsExtractor
+  ) {}
+
+  /**
+   * Returns accessible fields for Model type
+   */
+  ofType(subjectType: Extract<T, SubjectType>): string[] {
+    return permittedFieldsOf(this._ability, this._action, subjectType, {
+      fieldsFrom: this._getRuleFields(subjectType)
+    });
+  }
+
+  /**
+   * Returns accessible fields for particular document
+   */
+  of(subject: Exclude<T, SubjectType>): string[] {
+    return permittedFieldsOf(this._ability, this._action, subject, {
+      fieldsFrom: this._getRuleFields(this._ability.detectSubjectType(subject))
+    });
+  }
+
+  private _getRuleFields(type: SubjectType): GetRuleFields<RuleOf<AnyAbility>> {
+    return (rule) => (rule.fields || this._getAllFields(type));
+  }
+}