72 lines
2.1 KiB
JavaScript
72 lines
2.1 KiB
JavaScript
/**
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* Copyright (c) 2013-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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*/
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'use strict';
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jest.unmock('ViewabilityHelper');
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const ViewabilityHelper = require('ViewabilityHelper');
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let rowFrames;
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let data;
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function getFrameMetrics(index: number) {
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const frame = rowFrames[data[index].key];
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return {length: frame.height, offset: frame.y};
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}
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describe('computeViewableItems', function() {
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it('returns all 4 entirely visible rows as viewable', function() {
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rowFrames = {
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a: {y: 0, height: 50},
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b: {y: 50, height: 50},
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c: {y: 100, height: 50},
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d: {y: 150, height: 50},
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};
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data = [{key: 'a'}, {key: 'b'}, {key: 'c'}, {key: 'd'}];
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expect(ViewabilityHelper.computeViewableItems(50, data.length, 0, 200, getFrameMetrics))
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.toEqual([0, 1, 2, 3]);
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});
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it(
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'returns top 2 rows as viewable (1. entirely visible and 2. majority)',
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function() {
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rowFrames = {
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a: {y: 0, height: 50},
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b: {y: 50, height: 150},
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c: {y: 200, height: 50},
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d: {y: 250, height: 50},
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};
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data = [{key: 'a'}, {key: 'b'}, {key: 'c'}, {key: 'd'}];
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expect(ViewabilityHelper.computeViewableItems(50, data.length, 0, 200, getFrameMetrics))
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.toEqual([0, 1]);
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});
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it(
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'returns only 2nd row as viewable (majority)',
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function() {
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rowFrames = {
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a: {y: 0, height: 50},
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b: {y: 50, height: 150},
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c: {y: 200, height: 50},
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d: {y: 250, height: 50},
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};
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data = [{key: 'a'}, {key: 'b'}, {key: 'c'}, {key: 'd'}];
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expect(ViewabilityHelper.computeViewableItems(50, data.length, 25, 200, getFrameMetrics))
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.toEqual([1]);
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});
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it(
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'handles empty input',
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function() {
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rowFrames = {};
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data = [];
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expect(ViewabilityHelper.computeViewableItems(50, data.length, 0, 200, getFrameMetrics))
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.toEqual([]);
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});
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});
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