Merge pull request #23894 from Microsoft/importOutlining

Add outlining spans for Import declarations

src/harness/fourslash.ts

@@ -2419,7 +2419,7 @@ Actual: ${stringify(fullActual)}`);
             Harness.IO.log(stringify(spans));
         }
 
-        public verifyOutliningSpans(spans: Range[], kind?: "comment" | "region" | "code") {
+        public verifyOutliningSpans(spans: Range[], kind?: "comment" | "region" | "code" | "imports") {
             const actual = this.languageService.getOutliningSpans(this.activeFile.fileName);
 
             if (actual.length !== spans.length) {
@@ -4247,7 +4247,7 @@ namespace FourSlashInterface {
             this.state.verifyCurrentNameOrDottedNameSpanText(text);
         }
 
-        public outliningSpansInCurrentFile(spans: FourSlash.Range[], kind?: "comment" | "region" | "code") {
+        public outliningSpansInCurrentFile(spans: FourSlash.Range[], kind?: "comment" | "region" | "code" | "imports") {
             this.state.verifyOutliningSpans(spans, kind);
         }
 

src/services/outliningElementsCollector.ts

@@ -9,7 +9,27 @@ namespace ts.OutliningElementsCollector {
 
     function addNodeOutliningSpans(sourceFile: SourceFile, cancellationToken: CancellationToken, out: Push<OutliningSpan>): void {
         let depthRemaining = 40;
-        sourceFile.forEachChild(function walk(n) {
+        let current = 0;
+        const statements = sourceFile.statements;
+        const n = statements.length;
+        while (current < n) {
+            while (current < n && !isAnyImportSyntax(statements[current])) {
+                visitNonImportNode(statements[current]);
+                current++;
+            }
+            if (current === n) break;
+            const firstImport = current;
+            while (current < n && isAnyImportSyntax(statements[current])) {
+                addOutliningForLeadingCommentsForNode(statements[current], sourceFile, cancellationToken, out);
+                current++;
+            }
+            const lastImport = current - 1;
+            if (lastImport !== firstImport) {
+                out.push(createOutliningSpanFromBounds(findChildOfKind(statements[firstImport], SyntaxKind.ImportKeyword, sourceFile)!.getStart(sourceFile), statements[lastImport].getEnd(), OutliningSpanKind.Imports));
+            }
+        }
+
+        function visitNonImportNode(n: Node) {
             if (depthRemaining === 0) return;
             cancellationToken.throwIfCancellationRequested();
 
@@ -23,17 +43,17 @@ namespace ts.OutliningElementsCollector {
             depthRemaining--;
             if (isIfStatement(n) && n.elseStatement && isIfStatement(n.elseStatement)) {
                 // Consider an 'else if' to be on the same depth as the 'if'.
-                walk(n.expression);
-                walk(n.thenStatement);
+                visitNonImportNode(n.expression);
+                visitNonImportNode(n.thenStatement);
                 depthRemaining++;
-                walk(n.elseStatement);
+                visitNonImportNode(n.elseStatement);
                 depthRemaining--;
             }
             else {
-                n.forEachChild(walk);
+                n.forEachChild(visitNonImportNode);
             }
             depthRemaining++;
-        });
+        }
     }
 
     function addRegionOutliningSpans(sourceFile: SourceFile, out: Push<OutliningSpan>): void {

src/services/types.ts

@@ -824,9 +824,17 @@ namespace ts {
     }
 
     export const enum OutliningSpanKind {
+        /** Single or multi-line comments */
         Comment = "comment",
+
+        /** Sections marked by '// #region' and '// #endregion' comments */
         Region = "region",
-        Code = "code"
+
+        /** Declarations and expressions */
+        Code = "code",
+
+        /** Contiguous blocks of import declarations */
+        Imports = "imports"
     }
 
     export const enum OutputFileType {