Class LoopResolver

apps/sim/executor/variables/resolvers/loop.ts:28–301

const FOR_EACH_LOOP_CONTEXT_FIELDS = ['index', 'currentItem', 'items'] as const

export class LoopResolver implements Resolver {
  private loopNameToId: Map<string, string>

  constructor(
    private workflow: SerializedWorkflow,
    private navigatePathAsync?: AsyncPathNavigator
  ) {
    this.loopNameToId = new Map()
    for (const block of workflow.blocks) {
      if (workflow.loops[block.id] && block.metadata?.name) {
        this.loopNameToId.set(normalizeName(block.metadata.name), block.id)
      }
    }
  }

  private static OUTPUT_PROPERTIES = new Set(['result', 'results'])
  private static KNOWN_PROPERTIES = new Set(['iteration', 'index', 'item', 'currentItem', 'items'])

  canResolve(reference: string): boolean {
    if (!isReference(reference)) {
      return false
    }
    const parts = parseReferencePath(reference)
    if (parts.length === 0) {
      return false
    }
    const [type] = parts
    return type === REFERENCE.PREFIX.LOOP || this.loopNameToId.has(type)
  }

  resolve(reference: string, context: ResolutionContext): any {
    return this.resolveInternal(reference, context, false)
  }

  async resolveAsync(reference: string, context: ResolutionContext): Promise<any> {
    if (!this.navigatePathAsync) {
      return this.resolve(reference, context)
    }
    return this.resolveInternal(reference, context, true)
  }

  private async resolveInternal(
    reference: string,
    context: ResolutionContext,
    useAsyncPath: true
  ): Promise<any>
  private resolveInternal(reference: string, context: ResolutionContext, useAsyncPath: false): any
  private resolveInternal(
    reference: string,
    context: ResolutionContext,
    useAsyncPath: boolean
  ): any | Promise<any> {
    const parts = parseReferencePath(reference)
    if (parts.length === 0) {
      logger.warn('Invalid loop reference', { reference })
      return undefined
    }