function frexp( x ) {
	return fcn( x, [ 0.0, 0 ], 1, 0 );
}
Splits a double-precision floating-point number into a normalized fraction and an integer power of two.

@param {number} x - input value
@returns {Array<number>} output array

@example
var out = frexp( 4.0 );
// returns [ 0.5, 3 ]

@example
var out = frexp( 0.0 );
// returns [ 0.0, 0 ]

@example
var out = frexp( -0.0 );
// returns [ -0.0, 0 ]

@example
var out = frexp( NaN );
// returns [ NaN, 0 ]

@example
var out = frexp( Infinity );
// returns [ Infinity , 0 ]

@example
var out = frexp( -Infinity );
// returns [ -Infinity , 0 ]