Angular HtmlCollection displaying less items on console, whereas on expansion more items are displayed which could not be captured by code

Question

strong textThere is a library which on reference dynamically create a table , i want to get the scrollheight of this table But when I do: console.log(this.ElByClassName.nativeElement.getElementsByTagName('tbody'));

is showing

and on displaying the length its showing zero ,

but on expansion of this HTMLCollection I can see three array items , which i could not capture on using index , Does anyone has any idea why its so?