Trigger ngOnChanges for Array or Object

The solution turned out to be pretty simple, copy the contents into a new array or object with the javascript spread operator (...). This creates a new reference which triggers Angular change detection to call ngOnChanges().

Here's how to copy an Angular property of type array or object with the spread operator:

// copy array prop to trigger change detection

this.myArr = [...this.myArr];

// copy object prop to trigger change detection

this.myObj = {...this.myObj};