incrspace.js (2406B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var ceil = require( '@stdlib/math/base/special/ceil' ); 24 var isNumber = require( '@stdlib/assert/is-number' ).isPrimitive; 25 var isnan = require( '@stdlib/math/base/assert/is-nan' ); 26 var MAX_LENGTH = require( '@stdlib/constants/uint32/max' ); 27 28 29 // MAIN // 30 31 /** 32 * Generates a linearly spaced numeric array using a provided increment. 33 * 34 * @param {number} x1 - first array value 35 * @param {number} x2 - array element bound 36 * @param {number} [increment=1] - increment 37 * @throws {TypeError} first argument must be numeric 38 * @throws {TypeError} second argument must be numeric 39 * @throws {TypeError} third argument must be numeric 40 * @throws {RangeError} length of created array must be less than `4294967295` (`2**32 - 1`) 41 * @returns {Array} linearly spaced numeric array 42 * 43 * @example 44 * var arr = incrspace( 0, 11, 2 ); 45 * // returns [ 0, 2, 4, 6, 8, 10 ] 46 */ 47 function incrspace( x1, x2, increment ) { 48 var arr; 49 var len; 50 var inc; 51 var i; 52 if ( !isNumber( x1 ) || isnan( x1 ) ) { 53 throw new TypeError( 'invalid argument. Start must be numeric. Value: `' + x1 + '`.' ); 54 } 55 if ( !isNumber( x2 ) || isnan( x2 ) ) { 56 throw new TypeError( 'invalid argument. Stop must be numeric. Value: `' + x2 + '`.' ); 57 } 58 if ( arguments.length < 3 ) { 59 inc = 1; 60 } else { 61 inc = increment; 62 if ( !isNumber( inc ) || isnan( inc ) ) { 63 throw new TypeError( 'invalid argument. Increment must be numeric. Value: `' + inc + '`.' ); 64 } 65 } 66 len = ceil( ( x2-x1 ) / inc ); 67 68 if ( len > MAX_LENGTH ) { 69 throw new RangeError( 'invalid arguments. Generated array exceeds maximum array length.' ); 70 } 71 if ( len <= 1 ) { 72 return [ x1 ]; 73 } 74 arr = []; 75 arr.push( x1 ); 76 for ( i = 1; i < len; i++ ) { 77 arr.push( x1 + (inc*i) ); 78 } 79 return arr; 80 } 81 82 83 // EXPORTS // 84 85 module.exports = incrspace;