function not( a ) {
	return function( b ) {
		if ( Array.isArray( a ) ) {
			return !a.some(function( a ) {
				return a === b;
			});
		}
		return a !== b;
	};
}
not() should be used with Array.prototype.filter().

Return true only if b is different than any a.

For example:
[ 1, 2, 3 ].filter( not( 2 ) ) => [ 1, 3 ]
[ 1, 2, 3 ].filter( not( [ 2, 3 ] ) ) => [ 1 ]