getNodeFunction( builder ) {

		const nodeData = builder.getDataFromNode( this );

		let nodeFunction = nodeData.nodeFunction;

		if ( nodeFunction === undefined ) {

			nodeFunction = builder.parser.parseFunction( this.code );

			nodeData.nodeFunction = nodeFunction;

		}

		return nodeFunction;

	}
Returns the node function for this function node.

@param {NodeBuilder} builder - The current node builder.
@return {NodeFunction} The node function.