code: function applyMetadataEdit( metadata, edit ) {
  	switch ( edit.operation ) {
  		case 'update': {
  			// Either update existing key's value or append a new one at the end
  			const { key, value } = edit;
  			if ( find( metadata, { key } ) ) {
  				return map( metadata, m => ( m.key === key ? { key, value } : m ) );
  			}
  			return concat( metadata || [], { key, value } );
  		}
  		case 'delete': {
  			// Remove a value from the metadata array. If the key is not present,
  			// return unmodified original value.
  			const { key } = edit;
  			if ( find( metadata, { key } ) ) {
  				return reject( metadata, { key } );
  			}
  			return metadata;
  		}
  	}
  
  	return metadata;
  }
docs: /*
  Applies a metadata edit operation (either update or delete) to an existing array of
  metadata values.