palantir/blueprint

Overflow list: add option to keep children mounted

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#3,016 opened on Oct 11, 2018

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Package: coreType: feature requesthelp wanted

Description

Environment

  • Package version(s): 3.7.0

Feature request

Current overflow list removes children from DOM when its invisible, and they will be loaded again if they be visible again.

Sometimes the operation of remove and create elements costs too much performance and affects other components, like css animation.

If there is an option that allows keep children in the DOM tree (e.g. just set display: none to them), overflow list will have better performance.

Contributor guide

Tech stack
typescriptreacthtmlcss
Domain
frontendperformance
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
React component lifecycleCSS display property
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Investigate the OverflowList component in src/components/overflow list/overflowList.tsx. Currently, children are conditionally rendered based on visibility. To keep children mounted, modify the logic to always render children but toggle visibility using CSS display: none. Consider adding a new prop like `keepChildrenMounted` (boolean) to enable this behavior. Ensure that the component still correctly calculates overflow dimensions. Refer to existing tests in the same directory for guidance.