feat(core): Add validate function based rule condition (#2441)

Add a new rule condition `ValidateFunctionCondition` using a given `validate` function
to evaluate the condition result. This allows using arbitrary custom logic to evaluate
condition results.
This facilitates not using schema-conditions to be able to only use one pre-compiled AJV
for the data schema at a later stage.

Author: lucas-koehler

packages/core/src/models/uischema.ts

@@ -150,6 +150,27 @@ export interface SchemaBasedCondition extends BaseCondition, Scoped {
   failWhenUndefined?: boolean;
 }
 
+/** A condition using a validation function to determine its fulfillment. */
+export interface ValidateFunctionCondition extends BaseCondition, Scoped {
+  /**
+   * Validates whether the condition is fulfilled.
+   *
+   * @param data The data as resolved via the scope.
+   * @returns `true` if the condition is fulfilled */
+  validate: (context: ValidateFunctionContext) => boolean;
+}
+
+export interface ValidateFunctionContext {
+  /** The resolved data scoped to the `ValidateFunctionCondition`'s scope. */
+  data: unknown;
+  /** The full data of the form. */
+  fullData: unknown;
+  /** Optional instance path. Necessary when the actual data path can not be inferred via the scope alone as it is the case with nested controls. */
+  path: string | undefined;
+  /** The `UISchemaElement` containing the rule that uses the ValidateFunctionCondition, e.g. a `ControlElement` */
+  uischemaElement: UISchemaElement;
+}
+
 /**
  * A composable condition.
  */
@@ -179,7 +200,8 @@ export type Condition =
   | LeafCondition
   | OrCondition
   | AndCondition
-  | SchemaBasedCondition;
+  | SchemaBasedCondition
+  | ValidateFunctionCondition;
 
 /**
  * Common base interface for any UI schema element.

packages/core/src/util/runtime.ts

@@ -33,6 +33,7 @@ import {
   SchemaBasedCondition,
   Scopable,
   UISchemaElement,
+  ValidateFunctionCondition,
 } from '../models';
 import { resolveData } from './resolvers';
 import type Ajv from 'ajv';
@@ -51,24 +52,31 @@ const isSchemaCondition = (
   condition: Condition
 ): condition is SchemaBasedCondition => has(condition, 'schema');
 
+const isValidateFunctionCondition = (
+  condition: Condition
+): condition is ValidateFunctionCondition =>
+  has(condition, 'validate') &&
+  typeof (condition as ValidateFunctionCondition).validate === 'function';
+
 const getConditionScope = (condition: Scopable, path: string): string => {
   return composeWithUi(condition, path);
 };
 
 const evaluateCondition = (
   data: any,
+  uischema: UISchemaElement,
   condition: Condition,
   path: string,
   ajv: Ajv
 ): boolean => {
   if (isAndCondition(condition)) {
     return condition.conditions.reduce(
-      (acc, cur) => acc && evaluateCondition(data, cur, path, ajv),
+      (acc, cur) => acc && evaluateCondition(data, uischema, cur, path, ajv),
       true
     );
   } else if (isOrCondition(condition)) {
     return condition.conditions.reduce(
-      (acc, cur) => acc || evaluateCondition(data, cur, path, ajv),
+      (acc, cur) => acc || evaluateCondition(data, uischema, cur, path, ajv),
       false
     );
   } else if (isLeafCondition(condition)) {
@@ -80,6 +88,15 @@ const evaluateCondition = (
       return false;
     }
     return ajv.validate(condition.schema, value) as boolean;
+  } else if (isValidateFunctionCondition(condition)) {
+    const value = resolveData(data, getConditionScope(condition, path));
+    const context = {
+      data: value,
+      fullData: data,
+      path,
+      uischemaElement: uischema,
+    };
+    return condition.validate(context);
   } else {
     // unknown condition
     return true;
@@ -93,7 +110,7 @@ const isRuleFulfilled = (
   ajv: Ajv
 ): boolean => {
   const condition = uischema.rule.condition;
-  return evaluateCondition(data, condition, path, ajv);
+  return evaluateCondition(data, uischema, condition, path, ajv);
 };
 
 export const evalVisibility = (

packages/core/test/util/runtime.test.ts

@@ -33,6 +33,8 @@ import {
   OrCondition,
   RuleEffect,
   SchemaBasedCondition,
+  ValidateFunctionCondition,
+  ValidateFunctionContext,
 } from '../../src';
 import { evalEnablement, evalVisibility } from '../../src/util/runtime';
 
@@ -491,6 +493,119 @@ test('evalEnablement disable valid case', (t) => {
   t.is(evalEnablement(uischema, data, undefined, createAjv()), false);
 });
 
+// Add test case for ValidateFunctionCondition with evalEnablement (valid enable case)
+test('evalEnablement enable valid case based on ValidateFunctionCondition', (t) => {
+  const condition: ValidateFunctionCondition = {
+    scope: '#/properties/ruleValue',
+    validate: (context: ValidateFunctionContext) => context.data === 'bar',
+  };
+  const uischema: ControlElement = {
+    type: 'Control',
+    scope: '#/properties/value',
+    rule: {
+      effect: RuleEffect.ENABLE,
+      condition: condition,
+    },
+  };
+  const data = {
+    value: 'foo',
+    ruleValue: 'bar',
+  };
+  t.is(evalEnablement(uischema, data, undefined, createAjv()), true);
+});
+
+// Add test case for ValidateFunctionCondition with evalEnablement (invalid enable case)
+test('evalEnablement enable invalid case based on ValidateFunctionCondition', (t) => {
+  const condition: ValidateFunctionCondition = {
+    scope: '#/properties/ruleValue',
+    validate: (context: ValidateFunctionContext) => context.data === 'bar',
+  };
+  const uischema: ControlElement = {
+    type: 'Control',
+    scope: '#/properties/value',
+    rule: {
+      effect: RuleEffect.ENABLE,
+      condition: condition,
+    },
+  };
+  const data = {
+    value: 'foo',
+    ruleValue: 'foobar',
+  };
+  t.is(evalEnablement(uischema, data, undefined, createAjv()), false);
+});
+
+// Add test case for ValidateFunctionCondition with evalEnablement (valid disable case)
+test('evalEnablement disable valid case based on ValidateFunctionCondition', (t) => {
+  const condition: ValidateFunctionCondition = {
+    scope: '#/properties/ruleValue',
+    validate: (context: ValidateFunctionContext) => context.data === 'bar',
+  };
+  const uischema: ControlElement = {
+    type: 'Control',
+    scope: '#/properties/value',
+    rule: {
+      effect: RuleEffect.DISABLE,
+      condition: condition,
+    },
+  };
+  const data = {
+    value: 'foo',
+    ruleValue: 'bar',
+  };
+  t.is(evalEnablement(uischema, data, undefined, createAjv()), false);
+});
+
+// Add test case for ValidateFunctionCondition with evalEnablement (invalid disable case)
+test('evalEnablement disable invalid case based on ValidateFunctionCondition', (t) => {
+  const condition: ValidateFunctionCondition = {
+    scope: '#/properties/ruleValue',
+    validate: (context: ValidateFunctionContext) => context.data === 'bar',
+  };
+  const uischema: ControlElement = {
+    type: 'Control',
+    scope: '#/properties/value',
+    rule: {
+      effect: RuleEffect.DISABLE,
+      condition: condition,
+    },
+  };
+  const data = {
+    value: 'foo',
+    ruleValue: 'foobar',
+  };
+  t.is(evalEnablement(uischema, data, undefined, createAjv()), true);
+});
+
+// Test context properties for ValidateFunctionCondition
+test('ValidateFunctionCondition correctly passes context parameters', (t) => {
+  const condition: ValidateFunctionCondition = {
+    scope: '#/properties/ruleValue',
+    validate: (context: ValidateFunctionContext) => {
+      // Verify all context properties are passed correctly
+      return (
+        context.data === 'bar' &&
+        (context.fullData as any).value === 'foo' &&
+        context.path === undefined &&
+        (context.uischemaElement as any).scope === '#/properties/value'
+      );
+    },
+  };
+  const uischema: ControlElement = {
+    type: 'Control',
+    scope: '#/properties/value',
+    rule: {
+      effect: RuleEffect.ENABLE,
+      condition: condition,
+    },
+  };
+  const data = {
+    value: 'foo',
+    ruleValue: 'bar',
+  };
+  t.is(evalEnablement(uischema, data, undefined, createAjv()), true);
+});
+
 test('evalEnablement disable invalid case', (t) => {
   const leafCondition: LeafCondition = {
     type: 'LEAF',

packages/examples/src/examples/rule.ts

@@ -22,6 +22,7 @@
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.
 */
+import { ValidateFunctionContext } from '@jsonforms/core';
 import { registerExamples } from '../register';
 
 export const schema = {
@@ -44,6 +45,10 @@ export const schema = {
       type: 'string',
       enum: ['All', 'Some', 'Only potatoes'],
     },
+    vitaminDeficiency: {
+      type: 'string',
+      enum: ['None', 'Vitamin A', 'Vitamin B', 'Vitamin C'],
+    },
   },
 };
 
@@ -101,6 +106,23 @@ export const uischema = {
             },
           },
         },
+        {
+          type: 'Control',
+          label: 'Vitamin deficiency?',
+          scope: '#/properties/vitaminDeficiency',
+          rule: {
+            effect: 'SHOW',
+            condition: {
+              scope: '#',
+              validate: (context: ValidateFunctionContext) => {
+                return (
+                  !(context.data as any).dead &&
+                  (context.data as any).kindOfVegetables !== 'All'
+                );
+              },
+            },
+          },
+        },
       ],
     },
   ],