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perf: fix quadratic text/nth lookup (12.5s to 27ms) - #3127
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🦋 Changeset detectedLatest commit: b75a841 The changes in this PR will be included in the next version bump. This PR includes changesets to release 24 packages
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October 7, 2026 16:46
…lectors # Conflicts: # packages/sdk-go/internal/extensionassets/stagehand-extension.zip
…erf-text-selectors # Conflicts: # packages/sdk-go/internal/extensionassets/stagehand-extension.zip
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Why
Text lookups rescanned large lists repeatedly. On a page with 10,000 text matches:
count()nth(2).innerText()Medians across three local browser runs, with three calls per run. Every call returned the expected count and text.
What
Filter innermost matches by walking ancestors, resolve the requested index directly, and skip unnecessary DOM-node materialization for locator actions. Preserve match order, shadow-root boundaries, masks, cancellation and low-level node IDs.
How
1,178 extension/TypeScript tests and 21 browser integration tests passed. Builds and extension typecheck passed.
Medians of three local runs, each with 128 billing flows and four reused browsers. No LLM calls.
Summary by cubic
Fixes the quadratic text-selector lookup that made large text queries painfully slow. Across three local browser runs,
counton 10,000 matches fell from 4,124 to 26 ms, and reading the third match fell from 12,498 to 27 ms. Locator actions now skip unnecessary DOM-node materialization while low-level resolver callers retain frontend node IDs. Filtering of innermost matches is now a single pass over ancestors instead of an all-pairs containment comparison, andnthresolves the requested index directly so masks still acquire and release all matches.Behavior changes
nullwithout acquiring handles.Written for commit b75a841. Summary will update on new commits.