98 lines
2.1 KiB
JavaScript
98 lines
2.1 KiB
JavaScript
|
/**
|
||
|
|
* @license Apache-2.0
|
||
|
|
*
|
||
|
|
* Copyright (c) 2020 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 isnan = require( '@stdlib/math/base/assert/is-nan' );
|
||
|
|
var isNegativeZero = require( '@stdlib/math/base/assert/is-negative-zero' );
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Calculates the minimum value of a strided array via a callback function.
|
||
|
|
*
|
||
|
|
* @param {PositiveInteger} N - number of indexed elements
|
||
|
|
* @param {Collection} x - input array/collection
|
||
|
|
* @param {integer} stride - index increment
|
||
|
|
* @param {NonNegativeInteger} offset - starting index
|
||
|
|
* @param {Callback} clbk - callback
|
||
|
|
* @param {*} [thisArg] - execution context
|
||
|
|
* @returns {number} minimum value
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];
|
||
|
|
*
|
||
|
|
* function accessor( v ) {
|
||
|
|
* return v * 2.0;
|
||
|
|
* }
|
||
|
|
*
|
||
|
|
* var v = minBy( x.length, x, 1, 0, accessor );
|
||
|
|
* // returns -10.0
|
||
|
|
*/
|
||
|
|
function minBy( N, x, stride, offset, clbk, thisArg ) {
|
||
|
|
var min;
|
||
|
|
var ix;
|
||
|
|
var v;
|
||
|
|
var i;
|
||
|
|
|
||
|
|
if ( N <= 0 ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
if ( N === 1 || stride === 0 ) {
|
||
|
|
v = clbk.call( thisArg, x[ 0 ], 0, 0, x );
|
||
|
|
if ( v === void 0 ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
return v;
|
||
|
|
}
|
||
|
|
ix = offset;
|
||
|
|
for ( i = 0; i < N; i++ ) {
|
||
|
|
min = clbk.call( thisArg, x[ ix ], i, ix, x );
|
||
|
|
if ( min !== void 0 ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
ix += stride;
|
||
|
|
}
|
||
|
|
if ( i === N ) {
|
||
|
|
return NaN;
|
||
|
|
}
|
||
|
|
i += 1;
|
||
|
|
for ( i; i < N; i++ ) {
|
||
|
|
ix += stride;
|
||
|
|
v = clbk.call( thisArg, x[ ix ], i, ix, x );
|
||
|
|
if ( v === void 0 ) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
if ( isnan( v ) ) {
|
||
|
|
return v;
|
||
|
|
}
|
||
|
|
if ( v < min || ( v === min && isNegativeZero( v ) ) ) {
|
||
|
|
min = v;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return min;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = minBy;
|