Ionic - how to prevent error "TS2339: Property XXX does not exist on type"

Issue

I'm doing a simple loop through an Array and calling a method on each element.

this.scene.manager.scenes.forEach((scene) => {
  if(scene.refresh){
    scene.refresh();
  }
});

This code works, but it shows a compile error:

error TS2339: Property 'refresh' does not exist on type 'Scene'.

It's because one of array items is different from the others.

How can I prevent this compile error, since the condition if(scene.refresh){ is already handling it?

Solution

I think using a type assertion could be a better approach to inform TypeScript that the property does exist!

Something like this:

this.scene.manager.scenes.forEach((scene) => {
  if ('refresh' in scene) {
    (scene as any).refresh();
  }
});

Answered By - Freeman