private static showBonds()

in packages/ketcher-core/src/application/render/renderers/sequence/SequenceRenderer.ts [196:312]
103 lines of code
17 McCabe index (conditional complexity)

  private static showBonds(chainsCollection: ChainsCollection) {
    const handledMonomersToAttachmentPoints: Map<
      BaseMonomer,
      Set<AttachmentPointName>
    > = new Map();

    chainsCollection.chains.forEach((chain) => {
      chain.subChains.forEach((subChain) => {
        subChain.nodes.forEach((node) => {
          if (node instanceof EmptySequenceNode) {
            return;
          }

          node.monomers.forEach((monomer) => {
            if (!handledMonomersToAttachmentPoints.has(monomer)) {
              handledMonomersToAttachmentPoints.set(monomer, new Set());
            }

            monomer.forEachBond((polymerBond, attachmentPointName) => {
              const handledAttachmentPoints =
                handledMonomersToAttachmentPoints.get(
                  monomer,
                ) as Set<AttachmentPointName>;

              if (polymerBond instanceof MonomerToAtomBond) {
                const bondRenderer = new MonomerToAtomBondSequenceRenderer(
                  polymerBond,
                  node,
                );

                bondRenderer.show();
                polymerBond.setRenderer(bondRenderer);
                handledAttachmentPoints.add(attachmentPointName);

                return;
              }

              if (!subChain.bonds.includes(polymerBond)) {
                subChain.bonds.push(polymerBond);
              }
              if (!polymerBond.isSideChainConnection) {
                polymerBond.setRenderer(
                  new BackBoneBondSequenceRenderer(polymerBond),
                );
                return;
              }

              if (handledAttachmentPoints.has(attachmentPointName)) {
                return;
              }

              const anotherMonomer = polymerBond.getAnotherEntity(
                monomer,
              ) as BaseMonomer;

              // Skip handling side chains for sugar(R3) + base(R1) connections.
              if (
                (monomer instanceof Sugar &&
                  getRnaBaseFromSugar(monomer) === anotherMonomer) ||
                (anotherMonomer instanceof Sugar &&
                  getRnaBaseFromSugar(anotherMonomer) === monomer)
              ) {
                return;
              }

              let bondRenderer;

              // If side connection comes from rna base then take connected sugar and draw side connection from it
              // because for rna we display only one letter instead of three
              const connectedSugarToBase = getSugarFromRnaBase(anotherMonomer);
              if (
                isRnaBaseOrAmbiguousRnaBase(anotherMonomer) &&
                connectedSugarToBase
              ) {
                bondRenderer = new PolymerBondSequenceRenderer(
                  new PolymerBond(monomer, connectedSugarToBase),
                );
              } else {
                bondRenderer = new PolymerBondSequenceRenderer(polymerBond);
              }
              bondRenderer.show();
              polymerBond.setRenderer(bondRenderer);
              handledAttachmentPoints.add(attachmentPointName);

              if (!handledMonomersToAttachmentPoints.get(anotherMonomer)) {
                handledMonomersToAttachmentPoints.set(
                  anotherMonomer,
                  new Set(),
                );
              }
              const anotherMonomerHandledAttachmentPoints =
                handledMonomersToAttachmentPoints.get(
                  anotherMonomer,
                ) as Set<AttachmentPointName>;

              anotherMonomerHandledAttachmentPoints.add(
                anotherMonomer?.getAttachmentPointByBond(
                  polymerBond,
                ) as AttachmentPointName,
              );
            });
          });
        });
      });
      if (chain.isCyclic) {
        const polymerBond = chain.firstMonomer?.attachmentPointsToBonds
          .R1 as PolymerBond;
        const bondRenderer = new PolymerBondSequenceRenderer(
          polymerBond,
          chain.firstNode,
          chain.lastNonEmptyNode,
        );
        bondRenderer.show();
        polymerBond.setRenderer(bondRenderer);
      }
    });
  }