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Fire intersection events on isIntersecting changes #245

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Aug 29, 2017
Merged

Fire intersection events on isIntersecting changes #245

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33d6248
Fire intersection events on isIntersecting changes
nolanlawson Aug 28, 2017
a6e16dc
Use strict boolean for previousIsIntersecting
nolanlawson Aug 29, 2017
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22 changes: 14 additions & 8 deletions index.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -227,8 +227,9 @@ interface IntersectionObserver {
return.
2. Let |intersectionObserverRegistration| be
an {{IntersectionObserverRegistration}} record
with an {{IntersectionObserverRegistration/observer}} property set to |this|
and a {{IntersectionObserverRegistration/previousThresholdIndex}} property set to <code>-1</code>.
with an {{IntersectionObserverRegistration/observer}} property set to |this|,
a {{IntersectionObserverRegistration/previousThresholdIndex}} property set to <code>-1</code>,
and a {{IntersectionObserverRegistration/previousIsIntersecting}} property set to <code>false</code>.
3. Append |intersectionObserverRegistration|
to |target|'s internal {{[[RegisteredIntersectionObservers]]}} slot.
4. Add |target| to |this|'s internal {{[[ObservationTargets]]}} slot.
Expand Down Expand Up @@ -501,9 +502,9 @@ Element</h4>
which is initialized to an empty list.
This list holds <dfn interface>IntersectionObserverRegistration</dfn> records,
which have an <dfn attribute for=IntersectionObserverRegistration>observer</dfn> property
holding an {{IntersectionObserver}}
and a <dfn attribute for=IntersectionObserverRegistration>previousThresholdIndex</dfn> property
holding a number between -1 and the length of the observer's {{IntersectionObserver/thresholds}} property (inclusive).
holding an {{IntersectionObserver}}, a <dfn attribute for=IntersectionObserverRegistration>previousThresholdIndex</dfn> property
holding a number between -1 and the length of the observer's {{IntersectionObserver/thresholds}} property (inclusive), and
a <dfn attribute for=IntersectionObserverRegistration>previousIsIntersecting</dfn> property holding a boolean.

<h4 id='intersection-observer-private-slots'>
IntersectionObserver</h4>
Expand Down Expand Up @@ -616,18 +617,23 @@ To <dfn>run the update intersection observations steps</dfn> for a
zero area); otherwise, let |isIntersecting| be false.
8. If |targetArea| is non-zero, let |intersectionRatio| be |intersectionArea| divided by |targetArea|.<br>
Otherwise, let |intersectionRatio| be <code>1</code> if |isIntersecting| is true, or <code>0</code> if |isIntersecting| is false.
9. Let |thresholdIndex| be the index of the first entry in |observer|.{{thresholds}} whose value is greater than |intersectionRatio|, or the length of |observer|.{{thresholds}} if |intersectionRatio| is greater than the last entry in |observer|.{{thresholds}}.
9. Let |thresholdIndex| be the index of the first entry in |observer|.{{thresholds}} whose value is greater than |intersectionRatio|, or the length of |observer|.{{thresholds}} if |intersectionRatio| is greater than or equal to the last entry in |observer|.{{thresholds}}.
10. Let |intersectionObserverRegistration| be the {{IntersectionObserverRegistration}} record
in |target|'s internal {{[[RegisteredIntersectionObservers]]}} slot
whose {{IntersectionObserverRegistration/observer}} property is equal to |observer|.
11. Let |previousThresholdIndex| be the |intersectionObserverRegistration|'s
{{IntersectionObserverRegistration/previousThresholdIndex}} property.
12. If |thresholdIndex| does not equal |previousThresholdIndex|,
12. Let |previousIsIntersecting| be the |intersectionObserverRegistration|'s
{{IntersectionObserverRegistration/previousIsIntersecting}} property.
13. If |thresholdIndex| does not equal |previousThresholdIndex| or if
|isIntersecting| does not equal |previousIsIntersecting|,
<a>queue an IntersectionObserverEntry</a>,
passing in |observer|, |time|, |rootBounds|,
|boundingClientRect|, |intersectionRect|, |isIntersecting|, and |target|.
13. Assign |threshold| to |intersectionObserverRegistration|'s
14. Assign |threshold| to |intersectionObserverRegistration|'s
{{IntersectionObserverRegistration/previousThresholdIndex}} property.
15. Assign |isIntersecting| to |intersectionObserverRegistration|'s
{{IntersectionObserverRegistration/previousIsIntersecting}} property.

<h3 id='lifetime'>
IntersectionObserver Lifetime</h2>
Expand Down
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