import { Component } from '@angular/core';

@Component({
  selector: "my-app",
  template: `<h1>
    Hello {{name}}
  </h1>
  <my-app-custom-component></my-app-custom-component>
  `,
})

export class AppComponent  {
  name = "Angular";
}

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `<h1>
    Hello {{name}}
  </h1>
  <my-app-custom-component></my-app-custom-component>
  `,
})
export class AppComponent  { name = 'Angular'; }

--- 
+++ 
@@ -1,11 +1,14 @@
 import { Component } from '@angular/core';
 
 @Component({
-  selector: 'my-app',
+  selector: "my-app",
   template: `<h1>
     Hello {{name}}
   </h1>
   <my-app-custom-component></my-app-custom-component>
   `,
 })
-export class AppComponent  { name = 'Angular'; }
+
+export class AppComponent  {
+  name = "Angular";
+}
Replace single-quote -> double-quote. Add empty line
