feat: 🎸 detect OnPush change detection strategy in parser

Author: nivekcode

src/converters/component/component.converter.spec.ts

@@ -11,6 +11,7 @@ describe('Component converter', () => {
         selector: 'first',
         standalone: true,
         cva: true,
+        onPush: false,
         inputs: [],
         outputs: [],
         implementation: '',
@@ -25,6 +26,7 @@ describe('Component converter', () => {
         selector: 'second',
         standalone: false,
         cva: true,
+        onPush: true,
         inputs: [],
         outputs: [],
         implementation: '',
@@ -39,6 +41,7 @@ describe('Component converter', () => {
         selector: 'third',
         standalone: true,
         cva: false,
+        onPush: false,
         inputs: [],
         outputs: [],
         implementation: '',

src/parser/component/component.model.ts

@@ -7,6 +7,7 @@ export interface NgParselComponent extends NgParselOutput {
   selector: string;
   standalone: boolean;
   cva: boolean;
+  onPush: boolean;
   inputs: NgParselFieldDecorator[];
   outputs: NgParselFieldDecorator[];
   implementation: string;

src/parser/component/component.parser.spec.ts

@@ -38,6 +38,7 @@ describe('ComponentParser', () => {
       selector: 'my-test-comp',
       standalone: false,
       cva: false,
+      onPush: false,
       template: inlineTemplate,
       styles: [styles],
       inputs: [
@@ -47,6 +48,7 @@ describe('ComponentParser', () => {
           type: 'string',
           initializer: undefined,
           field: '@Input() foo: string',
+          jsDoc: undefined,
         },
       ],
       outputs: [
@@ -56,6 +58,7 @@ describe('ComponentParser', () => {
           type: undefined,
           initializer: 'new EventEmitter()',
           field: '@Output() bar = new EventEmitter()',
+          jsDoc: undefined,
         },
       ],
       implementation,
@@ -103,6 +106,7 @@ describe('ComponentParser', () => {
       selector: 'my-test-comp',
       standalone: true,
       cva: false,
+      onPush: false,
       template: inlineTemplate,
       styles: [styles],
       inputs: [
@@ -112,6 +116,7 @@ describe('ComponentParser', () => {
           type: 'string',
           initializer: undefined,
           field: '@Input() foo: string',
+          jsDoc: undefined,
         },
       ],
       outputs: [
@@ -121,6 +126,7 @@ describe('ComponentParser', () => {
           type: undefined,
           initializer: 'new EventEmitter()',
           field: '@Output() bar = new EventEmitter()',
+          jsDoc: undefined,
         },
       ],
       implementation,
@@ -195,4 +201,35 @@ describe('ComponentParser', () => {
 
     expect(parseComponent(ast, 'foo.component.ts').template).toBe('');
   });
+
+  it('should detect OnPush change detection strategy', () => {
+    const ast = tsquery.ast(`
+            @Component({
+                selector: 'my-test-comp',
+                template: '<h1>Foo</h1>',
+                styles: [],
+                changeDetection: ChangeDetectionStrategy.OnPush
+            })
+            export class MyTestComponent {}
+        `);
+
+    jest.spyOn(fs, 'readFileSync').mockReturnValue('');
+
+    expect(parseComponent(ast, 'foo.component.ts').onPush).toBeTruthy();
+  });
+
+  it('should default to false for change detection strategy when not specified', () => {
+    const ast = tsquery.ast(`
+            @Component({
+                selector: 'my-test-comp',
+                template: '<h1>Foo</h1>',
+                styles: []
+            })
+            export class MyTestComponent {}
+        `);
+
+    jest.spyOn(fs, 'readFileSync').mockReturnValue('');
+
+    expect(parseComponent(ast, 'foo.component.ts').onPush).toBeFalsy();
+  });
 });

src/parser/component/component.parser.ts

@@ -33,6 +33,7 @@ export function parseComponent(ast: ts.SourceFile, componentFilePath: string): N
     standalone: componentDecorators.standalone || false,
     template: template,
     cva: isCva(ast),
+    onPush: isOnPushChangeDetection(ast),
     styles: styles,
     implementation: componentImplementation,
     inputs: inputsAndOutputs.inputs,
@@ -48,6 +49,22 @@ function isCva(ast: ts.SourceFile): boolean {
   );
 }
 
+function isOnPushChangeDetection(ast: ts.SourceFile): boolean {
+  const changeDetectionNodes = tsquery(
+    ast,
+    'Decorator > CallExpression > ObjectLiteralExpression > PropertyAssignment:has(Identifier[name="changeDetection"])'
+  );
+
+  if (changeDetectionNodes.length === 0) {
+    return false;
+  }
+
+  const changeDetectionNode = changeDetectionNodes[0] as ts.PropertyAssignment;
+  const initializer = changeDetectionNode.initializer.getText();
+
+  return initializer.includes('ChangeDetectionStrategy.OnPush');
+}
+
 function fetchFileContent(filePath: string | undefined, componentFilePath: string): string {
   if (!filePath) {
     return '';