react-native/Libraries/Utilities/mapWithSeparator.js

30 lines
856 B
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule mapWithSeparator
* @flow
*/
'use strict';
function mapWithSeparator<TFrom, TTo>(
items: Array<TFrom>,
itemRenderer: (item: TFrom, index: number, items: Array<TFrom>) => TTo,
spacerRenderer: (index: number) => TTo,
): Array<TTo> {
const mapped = [];
if (items.length > 0) {
mapped.push(itemRenderer(items[0], 0, items));
for (let ii = 1; ii < items.length; ii++) {
mapped.push(spacerRenderer(ii - 1), itemRenderer(items[ii], ii, items));
}
}
return mapped;
}
module.exports = mapWithSeparator;