time-to-botec/js/node_modules/@stdlib/stats/iter/mmean/lib/main.js

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/**
* @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 setReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' );
var isIteratorLike = require( '@stdlib/assert/is-iterator-like' );
var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive;
var isFunction = require( '@stdlib/assert/is-function' );
var hasOwnProp = require( '@stdlib/assert/has-own-property' );
var iteratorSymbol = require( '@stdlib/symbol/iterator' );
var incrmmean = require( './../../../incr/mmean' );
// MAIN //
/**
* Returns an iterator which iteratively computes a moving arithmetic mean.
*
* @param {Iterator} iterator - input iterator
* @param {PositiveInteger} W - window size
* @throws {TypeError} first argument must be an iterator
* @throws {TypeError} second argument must be a positive integer
* @returns {Iterator} iterator
*
* @example
* var runif = require( '@stdlib/random/iter/uniform' );
*
* var rand = runif( -10.0, 10.0, {
* 'iter': 100
* });
*
* var it = itermmean( rand, 3 );
*
* var v = it.next().value;
* // returns <number>
*
* v = it.next().value;
* // returns <number>
*
* v = it.next().value;
* // returns <number>
*
* // ...
*/
function itermmean( iterator, W ) {
var iter;
var FLG;
var acc;
if ( !isIteratorLike( iterator ) ) {
throw new TypeError( 'invalid argument. First argument must be an iterator. Value: `' + iterator + '`.' );
}
if ( !isPositiveInteger( W ) ) {
throw new TypeError( 'invalid argument. Second argument must be a positive integer. Value: `' + W + '`.' );
}
acc = incrmmean( W );
// Create an iterator protocol-compliant object:
iter = {};
setReadOnly( iter, 'next', next );
setReadOnly( iter, 'return', end );
// If an environment supports `Symbol.iterator`, make the iterator iterable:
if ( iteratorSymbol && isFunction( iterator[ iteratorSymbol ] ) ) {
setReadOnly( iter, iteratorSymbol, factory );
}
return iter;
/**
* Returns an iterator protocol-compliant object containing the next iterated value.
*
* @private
* @returns {Object} iterator protocol-compliant object
*/
function next() {
var out;
var v;
if ( FLG ) {
return {
'done': true
};
}
out = {};
v = iterator.next();
if ( typeof v.value === 'number' ) {
out.value = acc( v.value );
} else if ( hasOwnProp( v, 'value' ) ) {
out.value = acc( NaN );
}
if ( v.done ) {
FLG = true;
out.done = true;
} else {
out.done = false;
}
return out;
}
/**
* Finishes an iterator.
*
* @private
* @param {*} [value] - value to return
* @returns {Object} iterator protocol-compliant object
*/
function end( value ) {
FLG = true;
if ( arguments.length ) {
return {
'value': value,
'done': true
};
}
return {
'done': true
};
}
/**
* Returns a new iterator.
*
* @private
* @returns {Iterator} iterator
*/
function factory() {
return itermmean( iterator[ iteratorSymbol ](), W );
}
}
// EXPORTS //
module.exports = itermmean;