function standalone2pkg( pkg ) {
	if ( !isString( pkg ) ) {
		throw new TypeError( format( 'invalid argument. Must provide a string. Value: `%s`.', pkg ) );
	}
	if ( hasOwnProp( STANDALONE_TO_PKG, pkg ) ) {
		return STANDALONE_TO_PKG[ pkg ];
	}
	return null;
}
Returns the internal package name associated with a provided standalone package name.

@param {string} pkg - standalone package name
@throws {TypeError} must provide a string
@returns {(string|null)} package name

@example
var v = standalone2pkg( '@stdlib/math-base-special-sin' );
// returns '@stdlib/math/base/special/sin'