From f1127e6e9471bc289fc233a6be240f9dba1cb69c Mon Sep 17 00:00:00 2001
From: Jesse Trinity <jetrinit@microsoft.com>
Date: Wed, 6 May 2020 14:59:21 -0700
Subject: [PATCH] extract symbol

---
 src/services/refactors/extractSymbol.ts | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/services/refactors/extractSymbol.ts b/src/services/refactors/extractSymbol.ts
index 8c6c8f6fc69..8b36c3afb62 100644
--- a/src/services/refactors/extractSymbol.ts
+++ b/src/services/refactors/extractSymbol.ts
@@ -8,7 +8,7 @@ namespace ts.refactor.extractSymbol {
      * Exported for tests.
      */
     export function getAvailableActions(context: RefactorContext): readonly ApplicableRefactorInfo[] {
-        const rangeToExtract = getRangeToExtract(context.file, getRefactorContextSpan(context));
+        const rangeToExtract = getRangeToExtract(context.file, getRefactorContextSpan(context), context.triggerReason);
 
         const targetRange = rangeToExtract.targetRange;
         if (targetRange === undefined) {
@@ -87,7 +87,7 @@ namespace ts.refactor.extractSymbol {
 
     /* Exported for tests */
     export function getEditsForAction(context: RefactorContext, actionName: string): RefactorEditInfo | undefined {
-        const rangeToExtract = getRangeToExtract(context.file, getRefactorContextSpan(context));
+        const rangeToExtract = getRangeToExtract(context.file, getRefactorContextSpan(context), /* triggerReason*/ { kind: "invoked" });
         const targetRange = rangeToExtract.targetRange!; // TODO:GH#18217
 
         const parsedFunctionIndexMatch = /^function_scope_(\d+)$/.exec(actionName);
@@ -186,18 +186,20 @@ namespace ts.refactor.extractSymbol {
      * not shown to the user, but can be used by us diagnostically)
      */
     // exported only for tests
-    export function getRangeToExtract(sourceFile: SourceFile, span: TextSpan): RangeToExtract {
+    export function getRangeToExtract(sourceFile: SourceFile, span: TextSpan, triggerReason?: RefactorTriggerReason): RangeToExtract {
         const { length } = span;
-
-        if (length === 0) {
+        if (length === 0 && triggerReason?.kind !== "invoked") {
             return { errors: [createFileDiagnostic(sourceFile, span.start, length, Messages.cannotExtractEmpty)] };
         }
+        const explicitCursorRequest = length === 0 && triggerReason?.kind === "invoked";
 
         // Walk up starting from the the start position until we find a non-SourceFile node that subsumes the selected span.
         // This may fail (e.g. you select two statements in the root of a source file)
-        const start = getParentNodeInSpan(getTokenAtPosition(sourceFile, span.start), sourceFile, span);
+        const startToken = getTokenAtPosition(sourceFile, span.start);
+        const start = explicitCursorRequest ? getExtractableParent(startToken): getParentNodeInSpan(startToken, sourceFile, span);
         // Do the same for the ending position
-        const end = getParentNodeInSpan(findTokenOnLeftOfPosition(sourceFile, textSpanEnd(span)), sourceFile, span);
+        const endToken = findTokenOnLeftOfPosition(sourceFile, textSpanEnd(span));
+        const end = explicitCursorRequest ? start : getParentNodeInSpan(endToken, sourceFile, span);
 
         const declarations: Symbol[] = [];
 
@@ -1832,6 +1834,10 @@ namespace ts.refactor.extractSymbol {
         }
     }
 
+    function getExtractableParent(node: Node | undefined): Node | undefined {
+        return findAncestor(node, node => node.parent && isExtractableExpression(node) && !isBinaryExpression(node.parent));
+    }
+
     /**
      * Computes whether or not a node represents an expression in a position where it could
      * be extracted.