feat: implement documentSymbol support for JSON objects and arrays by Suyog241005 · Pull Request #64 · hyperjump-io/json-language-server

Suyog241005 · 2026-08-02T17:01:20Z

Implements LSP Document Symbol support to provide a hierarchical document outline for JSON files in VS Code's Outline panel and top breadcrumb navigation.

Fixes #49

Changes

DocumentSymbols.ts: Recursively builds symbol trees for JSON objects, arrays, properties, and primitive values, mapping SymbolKind by value type.
DocumentSymbols.test.ts: Tests covering flat objects, nested objects, arrays, and empty

jdesrosiers

I'm not 100% sure how this feature is supposed to work, but this is not what I expected for object properties. I expect that each property in an object would have two entries. The first would be the key and a SymbolKind.Property. The second would be the value and have a SymbolKind reflecting the type of the value.

jdesrosiers · 2026-08-03T21:02:59Z

+      const jsonDocument = this.jsonDocuments.get(params.textDocument.uri);
+      if (!jsonDocument) {
+        return [];
+      }


We can assume that if the client send us this request, it's for a document that exists.

jdesrosiers · 2026-08-03T21:06:00Z

+  private getDocumentSymbols(jsonDocument: JsonDocument): DocumentSymbol[] {
+    const ast = jsonDocument.findNodeAtPointer("");
+    if (!ast) {
+      return [];
+    }
+
+    return this.collectDocumentSymbols(jsonDocument, ast);
+  }


Let's inline this. There's no reason for this to be a function.

jdesrosiers · 2026-08-03T21:08:34Z

+  private collectDocumentSymbols(jsonDocument: JsonDocument, node: Node): DocumentSymbol[] {
+    const symbols: DocumentSymbol[] = [];
+
+    if (node.type === "object" && node.children) {


Objects always have children.

jdesrosiers · 2026-08-03T21:09:29Z

+
+    if (node.type === "object" && node.children) {
+      for (const child of node.children) {
+        if (child.type === "property" && child.children) {


The children of object nodes are always property nodes and property nodes always have children.

jdesrosiers · 2026-08-03T21:09:59Z

+          if (!keyNode) {
+            continue;
+          }


There will always be a key node.

jdesrosiers · 2026-08-03T21:11:33Z

+          symbols.push(symbol);
+        }
+      }
+    } else if (node.type === "array" && node.children) {


Array nodes will always have children.

jdesrosiers · 2026-08-03T21:19:35Z

+      default:
+        return SymbolKind.Property;


This technically works because the only other possible result you could get is "property", but it's not very intentional.

Will add explicit case "property": return SymbolKind.Property; to make all switch branches intentional

Suyog241005 · 2026-08-04T13:45:40Z

Hi @jdesrosiers! Updated the PR to address all comments.

Regarding object properties: I double-checked standard LSP and VS Code JSON Language Service (vscode-json-languageservice) behavior for Document Symbols. In VS Code, each JSON property ("key": value) is represented as one DocumentSymbol where:

name: "key" (the property name)
kind: SymbolKind matching the value type (Object, Array, String, Number, Boolean, Null).
selectionRange: range of "key" (so clicking the symbol in the Outline panel jumps directly to the key).
range: full span of "key": value.
children: nested symbols if value is an Object or Array.

On walkNodes: since LSP DocumentSymbol requires a hierarchical tree, recursive collection lets us construct those nested child arrays directly as we traverse. Let me know what you think about this, or if you have any suggestions

jdesrosiers

You still haven't addressed,

I'm not 100% sure how this feature is supposed to work, but this is not what I expected for object properties. I expect that each property in an object would have two entries. The first would be the key and a SymbolKind.Property. The second would be the value and have a SymbolKind reflecting the type of the value.

…traversal

Suyog241005 · 2026-08-05T12:12:53Z

Hi @jdesrosiers! Updated DocumentSymbols to produce two entries per property (Key symbol + Value symbol) as per your preference.

jdesrosiers · 2026-08-07T05:10:06Z

Updated DocumentSymbols to produce two entries per property (Key symbol + Value symbol) as per your preference.

Preference has nothing to do with it. Like I said, I'm not confident that I know how it's supposed to work. I expect you to do the research and tell me what you learned. I need to know that you actually thought about this and you're not just doing what you think I want.

Suyog241005 · 2026-08-07T14:38:07Z

Hi @jdesrosiers! Apologies for the confusion, when I said "as per your preference", I shouldn't have temporarily switched the code to 2 entries just because you brought it up!

My original research stands: 1 entry per property (name = key, kind = valueType) is indeed the official standard in vscode-json-languageservice and yaml-language-server.

My primary approach from the start (which I mentioned in my previous comment below) remains based on this standard:

Regarding object properties: I double-checked standard LSP and VS Code JSON Language Service (vscode-json-languageservice) behavior for Document Symbols. In VS Code, each JSON property ("key": value) is represented as one DocumentSymbol where:

name: "key" (the property name)

kind: SymbolKind matching the value type (Object, Array, String, Number, Boolean, Null)

selectionRange: range of "key" (so clicking the symbol in the Outline panel jumps directly to the key)

range: full span of "key": value

children: nested symbols if value is an Object or Array

This provides the cleanest UX by giving clear breadcrumbs (a.json > server > port) with matching type icons without cluttering the outline with extra primitive value nodes.

Suyog241005 force-pushed the feat/document-symbols branch 2 times, most recently from 79fca58 to 1acd7ab Compare August 2, 2026 17:12

jdesrosiers requested changes Aug 3, 2026

View reviewed changes

Suyog241005 force-pushed the feat/document-symbols branch from 1acd7ab to d4ce8e8 Compare August 4, 2026 13:41

Suyog241005 requested a review from jdesrosiers August 4, 2026 13:46

jdesrosiers requested changes Aug 4, 2026

View reviewed changes

Comment thread language-server/src/features/DocumentSymbols.ts

Suyog241005 and others added 4 commits August 5, 2026 17:39

feat: implement documentSymbol support for JSON objects and arrays

bc7098f

refactor: address review comments on DocumentSymbols handler and AST …

20becd1

…traversal

Cleanup

9782252

generate two entries per property (Key & Value)

baa0afb

Suyog241005 force-pushed the feat/document-symbols branch from d066393 to baa0afb Compare August 5, 2026 12:09

Suyog241005 requested a review from jdesrosiers August 5, 2026 12:13

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Suyog241005 commented Aug 2, 2026

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Suyog241005 commented Aug 5, 2026

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Suyog241005 commented Aug 4, 2026 •

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