117 lines
2.9 KiB
JavaScript
117 lines
2.9 KiB
JavaScript
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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var isArrayLike = require( '@stdlib/assert/is-array-like-object' );
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var isPositiveZero = require( '@stdlib/math/base/assert/is-positive-zero' );
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var isNegativeZero = require( '@stdlib/math/base/assert/is-negative-zero' );
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var isnan = require( '@stdlib/math/base/assert/is-nan' );
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var PINF = require( '@stdlib/constants/float64/pinf' );
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var NINF = require( '@stdlib/constants/float64/ninf' );
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// MAIN //
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/**
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* Returns an accumulator function which incrementally computes minimum and maximum values.
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*
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* @param {Collection} [out] - output array
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* @throws {TypeError} output argument must be array-like
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* @returns {Function} accumulator function
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*
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* @example
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* var accumulator = incrminmax();
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*
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* var mm = accumulator();
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* // returns null
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*
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* mm = accumulator( 2.0 );
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* // returns [ 2.0, 2.0 ]
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*
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* mm = accumulator( -5.0 );
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* // returns [ -5.0, 2.0 ]
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*
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* mm = accumulator( 3.0 );
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* // returns [ -5.0, 3.0 ]
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*
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* mm = accumulator( 5.0 );
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* // returns [ -5.0, 5.0 ]
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*
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* mm = accumulator();
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* // returns [ -5.0, 5.0 ]
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*/
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function incrminmax( out ) {
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var minmax;
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var min;
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var max;
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var FLG;
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if ( arguments.length === 0 ) {
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minmax = [ 0.0, 0.0 ];
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} else {
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if ( !isArrayLike( out ) ) {
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throw new TypeError( 'invalid argument. Output argument must be an array-like object. Value: `' + out + '`.' );
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}
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minmax = out;
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}
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min = PINF;
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max = NINF;
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FLG = false;
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return accumulator;
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/**
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* If provided a value, the accumulator function returns updated minimum and maximum values. If not provided a value, the accumulator function returns the current minimum and maximum values.
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*
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* @private
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* @param {number} [x] - input value
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* @returns {(ArrayLikeObject|null)} output array or null
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*/
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function accumulator( x ) {
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if ( arguments.length === 0 ) {
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if ( FLG === false ) {
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return null;
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}
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minmax[ 0 ] = min; // Why? Because we cannot guarantee someone hasn't mutated the output array
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minmax[ 1 ] = max;
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return minmax;
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}
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FLG = true;
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if ( isnan( x ) ) {
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min = x;
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max = x;
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} else {
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if ( x < min || ( x === min && isNegativeZero( x ) ) ) {
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min = x;
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}
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if ( x > max || ( x === max && isPositiveZero( x ) ) ) {
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max = x;
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}
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}
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minmax[ 0 ] = min;
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minmax[ 1 ] = max;
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return minmax;
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}
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}
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// EXPORTS //
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module.exports = incrminmax;
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