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Fix minimumViewTime

Reviewed By: blairvanderhoof

Differential Revision: D4723575

fbshipit-source-id: a120eef4079a808bd3dead08df93989e1db3d96a
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sahrens authored and facebook-github-bot committed Mar 16, 2017
1 parent 63fa621 commit b1a63f00886ff4fbd557b391b83d38e81284f28f
@@ -49,7 +49,7 @@ export type ViewabilityConfig = {|
* layout.
*
* An item is said to be in a "viewable" state when any of the following
* is true for longer than `minViewTime` milliseconds (after an interaction if `waitForInteraction`
* is true for longer than `minimumViewTime` milliseconds (after an interaction if `waitForInteraction`
* is true):
*
* - Occupying >= `viewAreaCoveragePercentThreshold` of the view area XOR fraction of the item
@@ -145,7 +145,7 @@ class ViewabilityHelper {
renderRange?: {first: number, last: number}, // Optional optimization to reduce the scan size
): void {
const updateTime = Date.now();
if (this._lastUpdateTime === 0 && getFrameMetrics(0)) {
if (this._lastUpdateTime === 0 && itemCount > 0 && getFrameMetrics(0)) {
// Only count updates after the first item is rendered and has a frame.
this._lastUpdateTime = updateTime;
}
@@ -171,13 +171,13 @@ class ViewabilityHelper {
}
this._viewableIndices = viewableIndices;
this._lastUpdateTime = updateTime;
if (this._config.minViewTime && updateElapsed < this._config.minViewTime) {
if (this._config.minimumViewTime && updateElapsed < this._config.minimumViewTime) {
const handle = setTimeout(
() => {
this._timers.delete(handle);
this._onUpdateSync(viewableIndices, onViewableItemsChanged, createViewToken);
},
this._config.minViewTime,
this._config.minimumViewTime,
);
this._timers.add(handle);
} else {
@@ -249,9 +249,9 @@ describe('onUpdate', function() {
);
it(
'minViewTime delays callback',
'minimumViewTime delays callback',
function() {
const helper = new ViewabilityHelper({minViewTime: 350, viewAreaCoveragePercentThreshold: 0});
const helper = new ViewabilityHelper({minimumViewTime: 350, viewAreaCoveragePercentThreshold: 0});
rowFrames = {
a: {y: 0, height: 200},
b: {y: 200, height: 200},
@@ -279,9 +279,9 @@ describe('onUpdate', function() {
);
it(
'minViewTime skips briefly visible items',
'minimumViewTime skips briefly visible items',
function() {
const helper = new ViewabilityHelper({minViewTime: 350, viewAreaCoveragePercentThreshold: 0});
const helper = new ViewabilityHelper({minimumViewTime: 350, viewAreaCoveragePercentThreshold: 0});
rowFrames = {
a: {y: 0, height: 250},
b: {y: 250, height: 200},

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