GoogleChrome/lighthouse · error · Error

No timespan in progress

Error message

No timespan in progress

What it means

State-machine guard in UserFlow.endTimespan(). Requires currentTimespan to be set. Fires when endTimespan() is called without a prior startTimespan(), or when endTimespan() is called twice (the second call finds currentTimespan already cleared to undefined at line 213).

Solutions

1. Ensure startTimespan() was called before endTimespan()
2. Check flow.currentTimespan is set before calling endTimespan()
3. Do not call endTimespan() twice — guard with a currentTimespan check

Example fix

// before — endTimespan without startTimespan
await flow.endTimespan(); // throws

// after — start timespan first
await flow.startTimespan();
// ... interactions ...
await flow.endTimespan();

if (!flow.currentTimespan) {
  console.error('No timespan in progress — did you call startTimespan()?');
  return;
}
await flow.endTimespan();

/** @param {UserFlow} flow @returns {boolean} */
function canEndTimespan(flow) {
  return flow.currentTimespan != null && flow.currentNavigation == null;
}

When it happens

Trigger: Calling flow.endTimespan() when flow.currentTimespan is undefined. Happens when startTimespan() was never called, or after endTimespan() already completed and cleared the state.

Common situations: Forgot to call startTimespan() first. Double-calling endTimespan(). Calling endTimespan() by mistake instead of endNavigation(). Exception in a try/finally that caused endTimespan to run after it was already ended.

Related errors

• No navigation in progress
• Timespan already in progress
• Navigation already in progress
• Need at least one step before getting the result
• No lantern metrics available, did you run…

AI-assisted analysis of GoogleChrome/lighthouse@9515cd4e58 (2026-08-13). Data as JSON: /api/errors/f41c66a6c263a7c1. Report an issue: GitHub.

Appendix: source

Thrown at core/user-flow.js:208

  /**
   * @param {LH.UserFlow.StepFlags} [flags]
   */
  async startTimespan(flags) {
    if (this.currentTimespan) throw new Error('Timespan already in progress');
    if (this.currentNavigation) throw new Error('Navigation already in progress');

    const nextFlags = this._getNextFlags(flags);

    const timespan = await startTimespanGather(this._page, {
      config: this._options?.config,
      flags: nextFlags,
    });
    this.currentTimespan = {timespan, flags: nextFlags};
  }

  async endTimespan() {
    if (!this.currentTimespan) throw new Error('No timespan in progress');
    if (this.currentNavigation) throw new Error('Navigation already in progress');

    const {timespan, flags} = this.currentTimespan;
    const gatherResult = await timespan.endTimespanGather();
    this.currentTimespan = undefined;

    this._addGatherStep(gatherResult, flags);
  }

  /**
   * @param {LH.UserFlow.StepFlags} [flags]
   */
  async snapshot(flags) {
    if (this.currentTimespan) throw new Error('Timespan already in progress');
    if (this.currentNavigation) throw new Error('Navigation already in progress');

    const nextFlags = this._getNextFlags(flags);

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