deslice/src/deslice.js

Double-ended slice method (Array.prototype.slice).

/*
 * Copyright 2020 Alexengrig Dev.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

export default function (arr, start, end) {
    if (!Array.isArray(arr)) return arr;
    if (start === undefined) start = 0;
    if (end === undefined) end = arr.length;
    if (start < 0) {
        const max = arr.length + start;
        return [...arr.slice(start), ...arr.slice(0, end > max ? max : end)];
    } else {
        return arr.slice(start, end);
    }
}