function resolve( policy ) {
	var t = ( typeof policy );
	if ( t === 'string' ) {
		return ( str2enum( policy ) === null ) ? null : policy;
	}
	if ( t === 'number' ) {
		return enum2str( policy );
	}
	return null;
}
Returns the policy string associated with a supported ndarray data type policy value.

@param {*} policy - policy value
@returns {(string|null)} policy string or null

@example
var str2enum = require( '@stdlib/ndarray/base/output-policy-str2enum' );

var v = resolve( str2enum( 'same' ) );
// returns 'same'