TypeScript SDK - Evaluation

import { LangfuseClient } from "@langfuse/client";
import { startObservation, startActiveObservation } from "@langfuse/tracing";
 
const langfuse = new LangfuseClient();
 
// First, create a trace and an observation
const rootSpan = startObservation("my-trace");
const generation = rootSpan.startObservation(
  "my-generation",
  {},
  { asType: "generation" }
);
generation.end();
rootSpan.end();
 
// Score the specific generation (an observation)
langfuse.score.observation(generation, {
  name: "accuracy",
  value: 1,
  comment: "The answer was factually correct.",
});
 
// Score the entire trace
langfuse.score.trace(rootSpan, {
  name: "user-satisfaction",
  value: 0.9,
  comment: "User was happy with the overall result.",
});
 
// You can also score the currently active observation or trace
startActiveObservation("another-trace", (span) => {
  langfuse.score.activeObservation({
    name: "latency-score",
    value: 0.95,
  });
  langfuse.score.activeTrace({
    name: "quality-score",
    value: 0.88,
  });
});
 
// Finally, ensure scores are sent to the server
await langfuse.flush();