Ever wondered how twitter automatically loads more past data as you scroll down the page? 
Ok, I have some really nice tips for you. 
Using Vanilla JavaScript you could achieve this.
But I will be showing this example with Quasar ( Vue Framework )

Line-12: This is the data, which returns an object of "observer" with value of "null"

Line-17: This is the mounted hook, meaning, the function block in it will be run when this 
component is loaded / mounted on the app

Line-18: The "IntersectionObserver" class as seen from the MDN header image, is 
instantiated, and an arrow function is used to take the index '0'  of all the entries.

Line-19: The 'if' statement is used to check whether the first index exists and is 
intersecting, then emits a function to any parent component you wish to use this 
'intersectionOberser' component.

Line-24: Remember the returned data value "observer"?. this is now chained to a method 
called 'observe()', which is passed a parameter as the DOM element ( denoted / identified 
as $el in vue ).

Line-10: This is where I used the Observer component with a bound (bind) function 
"intersect" which was emitted from the "IntersectionObserver" child component with 
"$emit('intersect').

Line-23: I imported the "IntersectionObserver.vue" as Observer, and registered it under 
the component object, so i could render it as in line-10.

Line-50: This is the function the emitted 'intersect' calls, here, you can make your fetch 
calls to do wonders...