d2-ui
Version:
35 lines (32 loc) • 959 B
JavaScript
/**
* Copyright (c) 2013-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 insertIntoList
*
*/
/**
* Maintain persistence for target list when appending and prepending.
*/
;
function insertIntoList(targetList, toInsert, offset) {
if (offset === targetList.count()) {
toInsert.forEach(function (c) {
targetList = targetList.push(c);
});
} else if (offset === 0) {
toInsert.reverse().forEach(function (c) {
targetList = targetList.unshift(c);
});
} else {
var head = targetList.slice(0, offset);
var tail = targetList.slice(offset);
targetList = head.concat(toInsert, tail).toList();
}
return targetList;
}
module.exports = insertIntoList;