Function computeDiff

packages/arctic/src/session/summary.ts:186–212

(input: { messages: MessageV2.WithParts[] })

  )

  async function computeDiff(input: { messages: MessageV2.WithParts[] }) {
    let from: string | undefined
    let to: string | undefined

    // scan assistant messages to find earliest from and latest to
    // snapshot
    for (const item of input.messages) {
      if (!from) {
        for (const part of item.parts) {
          if (part.type === "step-start" && part.snapshot) {
            from = part.snapshot
            break
          }
        }
      }

      for (const part of item.parts) {
        if (part.type === "step-finish" && part.snapshot) {
          to = part.snapshot
          break
        }
      }
    }

    if (from && to) return Snapshot.diffFull(from, to)
    return []
  }
}