feat(rule): click event should be accompanied with key event (#761)

Author: mohammedzamakhan

src/index.ts

@@ -33,6 +33,7 @@ export { Rule as TemplateNoAnyRule } from './templateNoAnyRule';
 export { Rule as TemplateAccessibilityLabelForVisitor } from './templateAccessibilityLabelForRule';
 export { Rule as TemplateAccessibilityValidAriaRule } from './templateAccessibilityValidAriaRule';
 export { Rule as TemplatesAccessibilityAnchorContentRule } from './templateAccessibilityAnchorContentRule';
+export { Rule as TemplateClickEventsHaveKeyEventsRule } from './templateClickEventsHaveKeyEventsRule';
 export { Rule as TemplateAccessibilityAltTextRule } from './templateAccessibilityAltTextRule';
 export { Rule as TemplatesNoNegatedAsync } from './templatesNoNegatedAsyncRule';
 export { Rule as TemplateNoAutofocusRule } from './templateNoAutofocusRule';

src/templateClickEventsHaveKeyEventsRule.ts

@@ -0,0 +1,55 @@
+import { ElementAst } from '@angular/compiler';
+import { IRuleMetadata, RuleFailure, Rules } from 'tslint/lib';
+import { SourceFile } from 'typescript/lib/typescript';
+import { NgWalker } from './angular/ngWalker';
+import { BasicTemplateAstVisitor } from './angular/templates/basicTemplateAstVisitor';
+
+export class Rule extends Rules.AbstractRule {
+  static readonly metadata: IRuleMetadata = {
+    description: 'Ensures that the click event is accompanied with at least one key event keyup, keydown or keypress',
+    options: null,
+    optionsDescription: 'Not configurable.',
+    rationale: 'Keyboard is important for users with physical disabilities who cannot use mouse.',
+    ruleName: 'template-click-events-have-key-events',
+    type: 'functionality',
+    typescriptOnly: true
+  };
+
+  static readonly FAILURE_STRING = 'click must be accompanied by either keyup, keydown or keypress event for accessibility';
+
+  apply(sourceFile: SourceFile): RuleFailure[] {
+    return this.applyWithWalker(
+      new NgWalker(sourceFile, this.getOptions(), {
+        templateVisitorCtrl: TemplateClickEventsHaveKeyEventsVisitor
+      })
+    );
+  }
+}
+
+class TemplateClickEventsHaveKeyEventsVisitor extends BasicTemplateAstVisitor {
+  visitElement(el: ElementAst, context: any) {
+    this.validateElement(el);
+    super.visitElement(el, context);
+  }
+
+  private validateElement(el: ElementAst): void {
+    const hasClick = el.outputs.some(output => output.name === 'click');
+    if (!hasClick) {
+      return;
+    }
+    const hasKeyEvent = el.outputs.some(output => output.name === 'keyup' || output.name === 'keydown' || output.name === 'keypress');
+
+    if (hasKeyEvent) {
+      return;
+    }
+
+    const {
+      sourceSpan: {
+        end: { offset: endOffset },
+        start: { offset: startOffset }
+      }
+    } = el;
+
+    this.addFailureFromStartToEnd(startOffset, endOffset, Rule.FAILURE_STRING);
+  }
+}

test/templateClickEventsHaveKeyEventsRule.spec.ts

@@ -0,0 +1,45 @@
+import { Rule } from '../src/templateClickEventsHaveKeyEventsRule';
+import { assertAnnotated, assertSuccess } from './testHelper';
+
+const {
+  FAILURE_STRING,
+  metadata: { ruleName }
+} = Rule;
+
+describe(ruleName, () => {
+  describe('failure', () => {
+    it('should fail when click is not accompanied with key events', () => {
+      const source = `
+        @Component({
+          template: \`
+            <div (click)="onClick()"></div>
+            ~~~~~~~~~~~~~~~~~~~~~~~~~
+          \`
+        })
+        class Bar {}
+      `;
+      assertAnnotated({
+        message: FAILURE_STRING,
+        ruleName,
+        source
+      });
+    });
+  });
+
+  describe('success', () => {
+    it('should work find when click events are associated with key events', () => {
+      const source = `
+        @Component({
+          template: \`
+          <div (click)="onClick()" (keyup)="onKeyup()"></div>
+          <div (click)="onClick()" (keydown)="onKeyDown()"></div>
+          <div (click)="onClick()" (keypress)="onKeyPress()"></div>
+          <div (click)="onClick()" (keyup)="onKeyup()" (keydown)="onKeyDown()" (keypress)="onKeyPress()"></div>
+          \`
+        })
+        class Bar {}
+      `;
+      assertSuccess(ruleName, source);
+    });
+  });
+});