/** * @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 PINF = require( '@stdlib/constants/float64/pinf' ); var NINF = require( '@stdlib/constants/float64/ninf' ); var isnan = require( '@stdlib/math/base/assert/is-nan' ); // MAIN // /** * Returns an accumulator function which incrementally computes a range. * * @returns {Function} accumulator function * * @example * var accumulator = incrrange(); * * var range = accumulator(); * // returns null * * range = accumulator( 3.14 ); * // returns 0.0 * * range = accumulator( -5.0 ); * // returns 8.14 * * range = accumulator( 10.1 ); * // returns 15.1 * * range = accumulator(); * // returns 15.1 */ function incrrange() { var range; var max = NINF; var min = PINF; return accumulator; /** * If provided a value, the accumulator function returns an updated range. If not provided a value, the accumulator function returns the current range. * * @private * @param {number} [x] - new value * @returns {(number|null)} range or null */ function accumulator( x ) { if ( arguments.length === 0 ) { return ( range === void 0 ) ? null : range; } if ( isnan( x ) ) { min = x; max = x; } if ( x > max ) { max = x; } if ( x < min ) { min = x; } range = max - min; return range; } } // EXPORTS // module.exports = incrrange;