/**

* @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 isnan = require( '@stdlib/math-base-assert-is-nan' );

var isInfinite = require( '@stdlib/math-base-assert-is-infinite' );

var pow = require( '@stdlib/math-base-special-pow' );

var floor = require( '@stdlib/math-base-special-floor' );

var log10 = require( '@stdlib/math-base-special-log10' );

// MAIN //

/**

* Rounds a numeric value to the nearest power of `10` toward zero.

*

* @param {number} x - input value

* @returns {number} rounded value

*

* @example

* var v = trunc10( 3.141592653589793 );

* // returns 1.0

*

* @example

* var v = trunc10( 13.0 );

* // returns 10.0

*

* @example

* var v = trunc10( -0.314 );

* // returns -0.1

*/

function trunc10( x ) {

var sign;

if (

isnan( x ) ||

isInfinite( x ) ||

x === 0.0

) {

return x;

}

if ( x < 0 ) {

x = -x;

sign = -1.0;

} else {

sign = 1.0;

}

return sign * pow( 10.0, floor( log10( x ) ) );

}

// EXPORTS //

module.exports = trunc10;