function enum2str( policy ) {
	var v = hash[ policy ];
	return ( typeof v === 'string' ) ? v : null; // note: we include this guard to prevent walking the prototype chain
}
Returns the policy string associated with an output ndarray data type policy enumeration constant.

@param {integer} policy - policy enumeration constant
@returns {(string|null)} policy string or null

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

var v = str2enum( 'same' );
// returns <number>

var policy = enum2str( v );
// returns 'same'