mapbox/mapbox-gl-js

off('load') then on('load') does not work using setStyle

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#10,946 opened on Aug 19, 2021

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bug :lady_beetle:good first issue

Description

mapbox-gl-js version: v2.4.0

browser: Chrome Version 92.0.4515.159

Steps to Trigger Behavior

Reproduce steps

  1. add Map.on('load', func)
  2. add Map.off('load', func)
  3. add Map.on('load', func2)
  4. call Map.setStyle()

Link to Demonstration

https://jsfiddle.net/tsuzk/6o8m9nad

This should work because of this test

Expected Behavior

The Map.on('load', func2) should get called after Map.setStyle()

Actual Behavior

The Map.on('load', func2) does not get called after Map.setStyle()

Workaround

re-instantiate the map with a new stlye https://jsfiddle.net/tsuzk/6o8m9nad/1/

Other info

  • This occurs on v1.9.0 so it's not a new behavior in v2.

Priority

Low, since there is a proper workaround

Contributor guide

Tech stack
javascript
Domain
frontend
Issue type
bug
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
basic JavaScriptunderstanding of event listenersfamiliarity with mapbox gl js API
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Investigate the event handling in Mapbox GL JS, specifically how the 'load' event listener is managed when setStyle is called. Start by examining the source code of the Map class in /src/ui/map.js and the event system. The bug report references a test at test/unit/ui/map.test.js around lines 136-151 that expects the behavior to work, but it seems the test might be incorrect or the implementation fails in certain cases. Focus on the on/off methods for the 'load' event and how setStyle triggers the event re fire. Review any linked PRs or comments for additional context.