A Leak in the Shell – How Refactoring Autocomplete Broke Us and How We Fixed It

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Improving the autocomplete in MongoDB's database CLI seemed like a great idea. But when the team tried to flip the feature flag, things quickly started to go sideways: A story of memory leaks, bugs that touch the very core of JavaScript as a language, and hard-learned lessons about testing and performance.

This talk has been presented at Web Engineering Summit 2026, check out the latest edition of this Tech Conference.

Anna Henningsen
Anna Henningsen
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