122 lines
3.8 KiB
JavaScript
122 lines
3.8 KiB
JavaScript
/**
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* Copyright (c) 2015-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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* @format
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*/
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'use strict';
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const FillRateHelper = require('FillRateHelper');
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let rowFramesGlobal;
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const dataGlobal = [
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{key: 'header'},
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{key: 'a'},
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{key: 'b'},
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{key: 'c'},
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{key: 'd'},
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{key: 'footer'},
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];
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function getFrameMetrics(index: number) {
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const frame = rowFramesGlobal[dataGlobal[index].key];
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return {length: frame.height, offset: frame.y, inLayout: frame.inLayout};
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}
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function computeResult({helper, props, state, scroll}): number {
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helper.activate();
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return helper.computeBlankness(
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{
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data: dataGlobal,
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getItemCount: data2 => data2.length,
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initialNumToRender: 10,
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...(props || {}),
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},
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{first: 1, last: 2, ...(state || {})},
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{offset: 0, visibleLength: 100, ...(scroll || {})},
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);
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}
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describe('computeBlankness', function() {
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beforeEach(() => {
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FillRateHelper.setSampleRate(1);
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FillRateHelper.setMinSampleCount(0);
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});
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it('computes correct blankness of viewport', function() {
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const helper = new FillRateHelper(getFrameMetrics);
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rowFramesGlobal = {
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header: {y: 0, height: 0, inLayout: true},
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a: {y: 0, height: 50, inLayout: true},
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b: {y: 50, height: 50, inLayout: true},
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};
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let blankness = computeResult({helper});
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expect(blankness).toBe(0);
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blankness = computeResult({helper, state: {last: 1}});
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expect(blankness).toBe(0.5);
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blankness = computeResult({helper, scroll: {offset: 25}});
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expect(blankness).toBe(0.25);
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blankness = computeResult({helper, scroll: {visibleLength: 400}});
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expect(blankness).toBe(0.75);
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blankness = computeResult({helper, scroll: {offset: 100}});
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expect(blankness).toBe(1);
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});
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it('skips frames that are not in layout', function() {
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const helper = new FillRateHelper(getFrameMetrics);
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rowFramesGlobal = {
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header: {y: 0, height: 0, inLayout: false},
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a: {y: 0, height: 10, inLayout: false},
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b: {y: 10, height: 30, inLayout: true},
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c: {y: 40, height: 40, inLayout: true},
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d: {y: 80, height: 20, inLayout: false},
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footer: {y: 100, height: 0, inLayout: false},
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};
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const blankness = computeResult({helper, state: {last: 4}});
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expect(blankness).toBe(0.3);
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});
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it('sampling rate can disable', function() {
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let helper = new FillRateHelper(getFrameMetrics);
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rowFramesGlobal = {
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header: {y: 0, height: 0, inLayout: true},
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a: {y: 0, height: 40, inLayout: true},
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b: {y: 40, height: 40, inLayout: true},
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};
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let blankness = computeResult({helper});
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expect(blankness).toBe(0.2);
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FillRateHelper.setSampleRate(0);
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helper = new FillRateHelper(getFrameMetrics);
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blankness = computeResult({helper});
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expect(blankness).toBe(0);
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});
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it('can handle multiple listeners and unsubscribe', function() {
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const listeners = [jest.fn(), jest.fn(), jest.fn()];
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const subscriptions = listeners.map(listener =>
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FillRateHelper.addListener(listener),
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);
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subscriptions[1].remove();
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const helper = new FillRateHelper(getFrameMetrics);
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rowFramesGlobal = {
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header: {y: 0, height: 0, inLayout: true},
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a: {y: 0, height: 40, inLayout: true},
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b: {y: 40, height: 40, inLayout: true},
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};
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const blankness = computeResult({helper});
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expect(blankness).toBe(0.2);
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helper.deactivateAndFlush();
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const info0 = listeners[0].mock.calls[0][0];
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expect(info0.pixels_blank / info0.pixels_sampled).toBe(blankness);
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expect(listeners[1]).not.toBeCalled();
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const info1 = listeners[2].mock.calls[0][0];
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expect(info1.pixels_blank / info1.pixels_sampled).toBe(blankness);
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});
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});
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