Microsoft/monaco-editor

JavaScript folding ranges are not semantic

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#1,847 opened on Feb 24, 2020

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feature-requesthelp wantedopen for PRtypescript

Description

monaco-editor version: 0.20.0 Browser: Chrome OS: Windows Playground code that reproduces the issue:: https://microsoft.github.io/monaco-editor/playground.html#creating-the-editor-hello-world

Playground code

monaco.editor.create(document.getElementById("container"), {
	value: "function double(x) {\nreturn 2*x\n}\n\nfunction double2(x) {\n\treturn 2*x;\n}",
	language: "javascript",
    showFoldingControls: "always",	
});

image

I realized that the folding icon is hidden when all the lines of a Javascript function have no indentation. Using the same code but with tabs/spaces, the folding icon is shown.

In Visual Studio Code for Web Playground, I am also able to repro this issue.

Contributor guide

Tech stack
javascripttypescript
Domain
frontendtooling
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.
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.
clear
Prerequisites
JavaScriptMonaco Editor codebase
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The issue is that folding ranges are not shown for JavaScript functions without indentation. The bug likely lies in the JavaScript folding provider or the default indentation based folding logic in monaco editor. To fix, examine the folding provider in the source code (likely in src/folding or similar) and adjust the range detection to handle functions without indentation. The playground code provided in the issue can be used to test the fix.