code: function getNodeAsString( node ) {
  	if ( undefined === node ) {
  		return '';
  	}
  
  	switch ( node.type ) {
  		case 'BinaryExpression':
  			return getNodeAsString( node.left ) + getNodeAsString( node.right );
  
  		case 'StringLiteral':
  			return node.value;
  
  		default:
  			return '';
  	}
  }
docs: Given an argument node (or recursed node), attempts to return a string
  represenation of that node's value.
  
  @param {Object} node AST node.
  
  @return {string} String value.