Initial display doesn't respect threshold value.

[addlistener]

IntersectionObserver/polyfill/intersection-observer.js

Lines 334 to 350 in b38e62b

	if (!oldEntry) {
	this._queuedEntries.push(newEntry);
	} else if (rootIsInDom && rootContainsTarget) {
	// If the new entry intersection ratio has crossed any of the
	// thresholds, add a new entry.
	if (this._hasCrossedThreshold(oldEntry, newEntry)) {
	this._queuedEntries.push(newEntry);
	}
	} else {
	// If the root is not in the DOM or target is not contained within
	// root but the previous entry for this target had an intersection,
	// add a new record indicating removal.
	if (oldEntry && oldEntry.isIntersecting) {
	this._queuedEntries.push(newEntry);
	}
	}
	}, this);

@philipwalton Hi, Phillip! As I've found during my development process. When an entry is moved in or out of root element, the code doesn't run _hasCrossedThreshold . Is this behavior expected?

The MDN docs doesn't specify the behavior on show/hide, it just says when crossing the threshold the callback should be triggered. https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API#Intersection_change_callbacks

I tested on my Chrome 73 OSX, show/hide respects threshold value. However the native implementation of an android 4.4.4 native browser at hand behave just like your code does.

If this is the wrong behavior, I'd like to submit a pull request. And please let me know if this is intended.

[miketaylr]

However the native implementation of an android 4.4.4 native browser at hand behave just like your code does.

@jchnxu Some three years later, do more modern version of Android browser (Chrome?) still have this bug?

[miketaylr]

The polyfill is being removed in #499 (see #433 for discussion).

If you can still reproduce bugs in the native implementations, filing bugs in the various bug tracks would be really helpful.

I'm going to close this as wontfix, but thanks for taking the time to report this issue!

[addlistener]

However the native implementation of an android 4.4.4 native browser at hand behave just like your code does.

@jchnxu Some three years later, do more modern version of Android browser (Chrome?) still have this bug?

However I don't have that phone anymore. I don't know so I guess you don't need to care about it.

[miketaylr]

All good, thanks for the response.