Function convertMergeClause

packages/graph/src/astToSteps.ts:750–793

* Convert a MERGE clause into a MergeStep.

(mergeClause: MergeClause)

 * Convert a MERGE clause into a MergeStep.
 */
function convertMergeClause(mergeClause: MergeClause): MergeStep {
  let pattern: MergePatternConfig;

  if (mergeClause.pattern.type === "NodePattern") {
    const nodePattern = mergeClause.pattern as NodePattern;
    pattern = {
      type: "node",
      variable: nodePattern.variable,
      labels: nodePattern.labels,
      properties: convertPropertyMap(nodePattern.properties),
    };
  } else if (mergeClause.pattern.type === "MergeRelationshipPattern") {
    const relPattern = mergeClause.pattern as MergeRelationshipPattern;
    pattern = {
      type: "edge",
      variable: relPattern.edge.variable,
      label: relPattern.edge.label,
      direction: relPattern.edge.direction,
      properties: convertPropertyMap(relPattern.edge.properties),
      startVariable: relPattern.startVariable,
      endVariable: relPattern.endVariable,
    };
  } else {
    throw new Error(`Unknown MERGE pattern type: ${(mergeClause.pattern as any).type}`);
  }

  return new MergeStep({
    pattern,
    onCreate: mergeClause.onCreate
      ? mergeClause.onCreate.assignments.map((a) => ({
          variable: a.variable,
          property: a.property,
          value: convertSetValue(a.value),
        }))
      : undefined,
    onMatch: mergeClause.onMatch
      ? mergeClause.onMatch.assignments.map((a) => ({
          variable: a.variable,
          property: a.property,
          value: convertSetValue(a.value),
        }))
      : undefined,
  });
}

/**
 * Convert a WITH clause into a WithStep.