/** * @license Apache-2.0 * * Copyright (c) 2018 The Stdlib Authors. * * 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. */ 'use strict'; // MODULES // var clampIndex = require( './../../../base/clamp-index' ); var wrapIndex = require( './../../../base/wrap-index' ); // MAIN // /** * Returns an index given an index mode. * * @param {integer} idx - index * @param {NonNegativeInteger} max - maximum index * @param {string} mode - specifies how to handle an index outside the interval `[0,max]` * @throws {RangeError} index out-of-bounds * @returns {integer} index * * @example * var idx = ind( 2, 9, 'clamp' ); * // returns 2 * * idx = ind( 10, 9, 'clamp' ); * // returns 9 * * idx = ind( -1, 9, 'clamp' ); * // returns 0 * * @example * var idx = ind( 2, 9, 'wrap' ); * // returns 2 * * idx = ind( 10, 9, 'wrap' ); * // returns 0 * * idx = ind( -1, 9, 'wrap' ); * // returns 9 * * @example * var idx = ind( 2, 9, 'throw' ); * // returns 2 * * idx = ind( 10, 9, 'throw' ); * // throws * * idx = ind( -1, 9, 'throw' ); * // throws */ function ind( idx, max, mode ) { if ( mode === 'clamp' ) { return clampIndex( idx, max ); } if ( mode === 'wrap' ) { return wrapIndex( idx, max ); } if ( idx < 0 || idx > max ) { throw new RangeError( 'invalid argument. Index must be on the interval: [0,' + max + ']. Value: `' + idx + '`.' ); } return idx; } // EXPORTS // module.exports = ind;