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Record (and possibly rewind) JSDoc info, create JSDoc cache separately #2796

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ahejlsberg merged 1 commit into from
Feb 16, 2026
Merged

Record (and possibly rewind) JSDoc info, create JSDoc cache separately #2796

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8 changes: 1 addition & 7 deletions internal/parser/jsdoc.go
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Original file line number Diff line number Diff line change
Expand Up @@ -31,12 +31,6 @@ func (p *Parser) withJSDoc(node *ast.Node, hasJSDoc bool) []*ast.Node {
if !hasJSDoc {
return nil
}

if p.jsdocCache == nil {
p.jsdocCache = make(map[*ast.Node][]*ast.Node, strings.Count(p.sourceText, "/**"))
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@jakebailey jakebailey Feb 16, 2026

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This presizing was important for perf; can this be retained somewhere? Maybe not, given we don't want to do this when we're not parsing out jsdoc.

(I can test the perf of this later)

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@ahejlsberg ahejlsberg Feb 16, 2026

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I think presizing is a lot more important for maps. We now collect the JSDoc information in an array and then build the map as we finalize the source file. The array is subject to reallocation, but the map is preallocated in its exact final size. We could presize the array, but I doubt it matters much.

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@jakebailey jakebailey Feb 16, 2026 •
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I'll profile it later, not blocking

(This is a map, though)

} else if _, ok := p.jsdocCache[node]; ok {
panic("tried to set JSDoc on a node with existing JSDoc")
}
// Should only be called once per node
p.hasDeprecatedTag = false
ranges := GetJSDocCommentRanges(&p.factory, p.jsdocCommentRangesSpace, node, p.sourceText)
Expand All @@ -61,7 +55,7 @@ func (p *Parser) withJSDoc(node *ast.Node, hasJSDoc bool) []*ast.Node {
if p.scriptKind == core.ScriptKindJS || p.scriptKind == core.ScriptKindJSX {
p.reparseTags(node, jsdoc)
}
p.jsdocCache[node] = jsdoc
p.jsdocInfos = append(p.jsdocInfos, JSDocInfo{parent: node, jsDocs: jsdoc})
return jsdoc
}
return nil
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20 changes: 18 additions & 2 deletions internal/parser/parser.go
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Expand Up @@ -48,6 +48,11 @@ const (

type ParsingContexts int

type JSDocInfo struct {
parent *ast.Node
jsDocs []*ast.Node
}

type Parser struct {
scanner *scanner.Scanner
factory ast.NodeFactory
Expand All @@ -74,7 +79,7 @@ type Parser struct {
notParenthesizedArrow collections.Set[int]
nodeSlicePool core.Pool[*ast.Node]
stringSlicePool core.Pool[string]
jsdocCache map[*ast.Node][]*ast.Node
jsdocInfos []JSDocInfo
possibleAwaitSpans []int
jsdocCommentsSpace []string
jsdocCommentRangesSpace []ast.CommentRange
Expand Down Expand Up @@ -264,6 +269,7 @@ type ParserState struct {
contextFlags ast.NodeFlags
diagnosticsLen int
jsDiagnosticsLen int
jsdocInfosLen int
reparsedClonesLen int
statementHasAwaitIdentifier bool
hasParseError bool
Expand All @@ -275,6 +281,7 @@ func (p *Parser) mark() ParserState {
contextFlags: p.contextFlags,
diagnosticsLen: len(p.diagnostics),
jsDiagnosticsLen: len(p.jsDiagnostics),
jsdocInfosLen: len(p.jsdocInfos),
reparsedClonesLen: len(p.reparsedClones),
statementHasAwaitIdentifier: p.statementHasAwaitIdentifier,
hasParseError: p.hasParseError,
Expand All @@ -287,6 +294,7 @@ func (p *Parser) rewind(state ParserState) {
p.contextFlags = state.contextFlags
p.diagnostics = p.diagnostics[0:state.diagnosticsLen]
p.jsDiagnostics = p.jsDiagnostics[0:state.jsDiagnosticsLen]
p.jsdocInfos = p.jsdocInfos[0:state.jsdocInfosLen]
p.reparsedClones = p.reparsedClones[0:state.reparsedClonesLen]
p.statementHasAwaitIdentifier = state.statementHasAwaitIdentifier
p.hasParseError = state.hasParseError
Expand Down Expand Up @@ -386,12 +394,20 @@ func (p *Parser) finishSourceFile(result *ast.SourceFile, isDeclarationFile bool
result.NodeCount = p.factory.NodeCount()
result.TextCount = p.factory.TextCount()
result.IdentifierCount = p.identifierCount
result.SetJSDocCache(p.jsdocCache)
result.SetJSDocCache(p.createJSDocCache())
slices.SortFunc(p.reparsedClones, ast.CompareNodePositions)
result.ReparsedClones = slices.Clone(p.reparsedClones)
ast.SetExternalModuleIndicator(result, p.opts.ExternalModuleIndicatorOptions)
}

func (p *Parser) createJSDocCache() map[*ast.Node][]*ast.Node {
result := make(map[*ast.Node][]*ast.Node, len(p.jsdocInfos))
for _, info := range p.jsdocInfos {
result[info.parent] = info.jsDocs
}
return result
}

func (p *Parser) parseToplevelStatement(i int) *ast.Node {
p.statementHasAwaitIdentifier = false
statement := p.parseStatement()
Expand Down
6 changes: 3 additions & 3 deletions internal/parser/reparser.go
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Expand Up @@ -96,7 +96,7 @@ func (p *Parser) reparseUnhosted(tag *ast.Node, parent *ast.Node, jsDoc *ast.Nod
}
typeAlias.AsTypeAliasDeclaration().Type = t
p.finishReparsedNode(typeAlias, tag)
p.jsdocCache[typeAlias] = []*ast.Node{jsDoc}
p.jsdocInfos = append(p.jsdocInfos, JSDocInfo{parent: typeAlias, jsDocs: []*ast.Node{jsDoc}})
typeAlias.Flags |= ast.NodeFlagsHasJSDoc
p.reparseList = append(p.reparseList, typeAlias)
case ast.KindJSDocCallbackTag:
Expand All @@ -108,7 +108,7 @@ func (p *Parser) reparseUnhosted(tag *ast.Node, parent *ast.Node, jsDoc *ast.Nod
typeAlias := p.factory.NewJSTypeAliasDeclaration(nil, p.addDeepCloneReparse(callbackTag.FullName), nil, functionType)
typeAlias.AsTypeAliasDeclaration().TypeParameters = p.gatherTypeParameters(jsDoc, tag)
p.finishReparsedNode(typeAlias, tag)
p.jsdocCache[typeAlias] = []*ast.Node{jsDoc}
p.jsdocInfos = append(p.jsdocInfos, JSDocInfo{parent: typeAlias, jsDocs: []*ast.Node{jsDoc}})
typeAlias.Flags |= ast.NodeFlagsHasJSDoc
p.reparseList = append(p.reparseList, typeAlias)
case ast.KindJSDocImportTag:
Expand Down Expand Up @@ -239,7 +239,7 @@ func (p *Parser) reparseJSDocComment(node *ast.Node, tag *ast.Node) {
if comment := tag.CommentList(); comment != nil {
propJSDoc := p.factory.NewJSDoc(comment, nil)
p.finishReparsedNode(propJSDoc, tag)
p.jsdocCache[node] = []*ast.Node{propJSDoc}
p.jsdocInfos = append(p.jsdocInfos, JSDocInfo{parent: node, jsDocs: []*ast.Node{propJSDoc}})
node.Flags |= ast.NodeFlagsHasJSDoc
}
}
Expand Down