scroll.js•690 B
'use strict';
Object.defineProperty(exports, '__esModule', {
value: true
});
exports.default = scroll;
/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
function scroll(size, {offset, max}) {
let start = 0;
let index = Math.min(offset, size);
const halfScreen = max / 2;
if (index <= halfScreen) {
start = 0;
} else {
if (size >= max) {
start = Math.min(index - halfScreen - 1, size - max);
}
index = Math.min(index - start, size);
}
return {
end: Math.min(size, start + max),
index,
start
};
}