Method traverse

packages/graph/src/Steps.ts:5461–5656

(
    source: GraphSource<any>,
    input: Iterable<TraversalPath<any, any, any>>,
    context?: QueryContext,
  )

  }

  public *traverse(
    source: GraphSource<any>,
    input: Iterable<TraversalPath<any, any, any>>,
    context?: QueryContext,
  ): IterableIterator<TraversalPath<any, any, any>> {
    const { variable, listExpression } = this.config;

    for (const path of input) {
      this.traversed++;

      // Get the list to iterate over
      let listValue: readonly any[];

      if (listExpression) {
        if (listExpression.type === "literal") {
          // Literal list - use the values directly
          listValue = listExpression.values;
        } else if (listExpression.type === "property") {
          // Property access - get the property from the variable bound in the path
          const variablePath = path.get(listExpression.variable);
          if (!variablePath) {
            // Variable not found - skip this path but still yield it
            this.emitted++;
            yield path;
            continue;
          }
          const element = variablePath.value;
          if (element instanceof Vertex || element instanceof Edge) {
            const propValue = element.get(listExpression.property as never);
            if (!Array.isArray(propValue)) {
              // Property is not an array - skip this path but still yield it
              this.emitted++;
              yield path;
              continue;
            }
            listValue = propValue;
          } else {
            // Not a graph element - skip this path but still yield it
            this.emitted++;
            yield path;
            continue;
          }
        } else if (listExpression.type === "variable") {
          // Variable reference - get the value directly from the path
          const variablePath = path.get(listExpression.variable);
          if (!variablePath) {
            // Variable not found - skip this path but still yield it
            this.emitted++;
            yield path;
            continue;
          }
          const value = variablePath.value;
          if (!Array.isArray(value)) {
            // Not an array - skip this path but still yield it
            this.emitted++;
            yield path;
            continue;
          }