All files / cosd/lib main.js

69.76% Statements 60/86
100% Branches 1/1
0% Functions 0/1
69.76% Lines 60/86

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 871x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x                                                     1x 1x 1x 1x 1x  
/**
* @license Apache-2.0
*
* Copyright (c) 2024 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 deg2rad = require( '@stdlib/math/base/special/deg2rad' );
var kernelSin = require( '@stdlib/math/base/special/kernel-sin' );
var kernelCos = require( '@stdlib/math/base/special/kernel-cos' );
var fmod = require( '@stdlib/math/base/special/fmod' );
var abs = require( '@stdlib/math/base/special/abs' );
var isnan = require( '@stdlib/math/base/assert/is-nan' );
var isInfinite = require( '@stdlib/math/base/assert/is-infinite' );
 
 
// MAIN //
 
/**
* Computes the cosine of an angle measured in degrees.
*
* @param {number} x - input value (in degrees)
* @returns {number} cosine
*
* @example
* var v = cosd( 0.0 );
* // returns 1.0
*
* @example
* var v = cosd( 90.0 );
* // returns 0.0
*
* @example
* var v = cosd( 60.0 );
* // returns ~0.5
*
* @example
* var v = cosd( NaN );
* // returns NaN
*/
function cosd( x ) {
	var rx;

	if (
		isInfinite( x ) ||
		isnan( x )
	) {
		return NaN;
	}

	rx = abs( fmod( x, 360.0 ) );

	if ( rx <= 45.0 ) {
		return kernelCos( deg2rad( rx ), 0.0 );
	}
	if ( rx < 135.0 ) {
		return kernelSin( deg2rad( 90.0-rx ), 0.0 );
	}
	if ( rx <= 225.0 ) {
		return -kernelCos( deg2rad( 180.0-rx ), 0.0 );
	}
	if ( rx < 315.0 ) {
		return kernelSin( deg2rad( rx-270.0 ), 0.0 );
	}
	return kernelCos( deg2rad( 360.0-rx ), 0.0 );
}
 
 
// EXPORTS //
 
module.exports = cosd;