feat(json-schema): add const validator (#1825)

ngx-formly · Oct 8, 2019 · 4607b1c · 4607b1c
1 parent 92bb6d7
commit 4607b1c
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Showing 3 changed files with 36 additions and 9 deletions.
diff --git a/demo/src/app/examples/advanced/json-schema/app.module.ts b/demo/src/app/examples/advanced/json-schema/app.module.ts
@@ -47,6 +47,10 @@ export function exclusiveMaximumValidationMessage(err, field: FormlyFieldConfig)
   return `should be < ${field.templateOptions.step}`;
 }
 
+export function constValidationMessage(err, field: FormlyFieldConfig) {
+  return `should be equal to constant "${field.templateOptions.const}"`;
+}
+
 @NgModule({
   imports: [
     CommonModule,
@@ -68,6 +72,7 @@ export function exclusiveMaximumValidationMessage(err, field: FormlyFieldConfig)
         { name: 'minItems', message: minItemsValidationMessage },
         { name: 'maxItems', message: maxItemsValidationMessage },
         { name: 'uniqueItems', message: 'should NOT have duplicate items' },
+        { name: 'const', message: constValidationMessage },
       ],
       types: [
         { name: 'string', extends: 'input' },

diff --git a/src/core/json-schema/src/formly-json-schema.service.spec.ts b/src/core/json-schema/src/formly-json-schema.service.spec.ts
@@ -514,15 +514,29 @@ describe('Service: FormlyJsonschema', () => {
         });
       });
 
-      // TODO: discuss const support possibly as hidden, already set field
-      // it('should support cosnt', () => {
-      //   const schema: JSONSchema7 = {
-      //     type: 'string',
-      //     const: 'string Const',
-      //   };
-
-      //   const config = formlyJsonschema.toFieldConfig(schema);
-      // });
+      it('should support const as hidden', () => {
+        const schema: JSONSchema7 = { const: 'const' };
+        const { type, defaultValue, validators } = formlyJsonschema.toFieldConfig(schema);
+        expect(type).toBeUndefined();
+        expect(defaultValue).toEqual('const');
+        expect(validators).toBeDefined();
+      });
+
+      it('should support const as type', () => {
+        const schema: JSONSchema7 = {
+          type: 'string',
+          const: 'const',
+        };
+        const { type, defaultValue, validators: { const: constValidator } } = formlyJsonschema.toFieldConfig(schema);
+
+        expect(type).toEqual('string');
+        expect(defaultValue).toBeUndefined();
+
+        expect(constValidator).toBeDefined();
+        expect(constValidator(new FormControl(null))).toBeFalsy();
+        expect(constValidator(new FormControl(4))).toBeFalsy();
+        expect(constValidator(new FormControl('const'))).toBeTruthy();
+      });
     });
 
     // https://json-schema.org/latest/json-schema-validation.html#rfc.section.9

diff --git a/src/core/json-schema/src/formly-json-schema.service.ts b/src/core/json-schema/src/formly-json-schema.service.ts
@@ -203,6 +203,14 @@ export class FormlyJsonschema {
       }
     }
 
+    if (schema.hasOwnProperty('const')) {
+      field.templateOptions.const = schema.const;
+      this.addValidator(field, 'const', ({ value }) => value === schema.const);
+      if (!field.type) {
+        field.defaultValue = schema.const;
+      }
+    }
+
     if (this.isEnum(schema)) {
       field.templateOptions.multiple = field.type === 'array';
       field.type = 'enum';