getShared( builder ) {

		const hash = this.getHash( builder );
		const nodeFromHash = builder.getNodeFromHash( hash );

		return nodeFromHash || this;

	}
This method is used during the build process of a node and ensures
equal nodes are not built multiple times but just once. For example if
`attribute( 'uv' )` is used multiple times by the user, the build
process makes sure to process just the first node.

@param {NodeBuilder} builder - The current node builder.
@return {Node} The shared node if possible. Otherwise `this` is returned.