40 lines
766 B
JavaScript
40 lines
766 B
JavaScript
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/**
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* Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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*
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*/
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'use strict';
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Object.defineProperty(exports, '__esModule', {
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value: true
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});
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exports.default = scroll;
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function scroll(size, _ref) {
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let offset = _ref.offset,
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max = _ref.max;
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let start = 0;
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let index = Math.min(offset, size);
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const halfScreen = max / 2;
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if (index <= halfScreen) {
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start = 0;
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} else {
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if (size >= max) {
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start = Math.min(index - halfScreen - 1, size - max);
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}
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index = Math.min(index - start, size);
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}
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return {
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end: Math.min(size, start + max),
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index: index,
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start: start
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};
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}
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