extractMethod: Don't try to extract a single token (#18090)

* extractMethod: Don't try to extract a single token

* Update tests

Author: Andy

src/services/refactors/extractMethod.ts

@@ -95,7 +95,7 @@ namespace ts.refactor.extractMethod {
         export const CannotExtractRangeThatContainsWritesToReferencesLocatedOutsideOfTheTargetRangeInGenerators: DiagnosticMessage = createMessage("Cannot extract range containing writes to references located outside of the target range in generators.");
         export const TypeWillNotBeVisibleInTheNewScope = createMessage("Type will not visible in the new scope.");
         export const FunctionWillNotBeVisibleInTheNewScope = createMessage("Function will not visible in the new scope.");
-        export const InsufficientSelection = createMessage("Select more than a single identifier.");
+        export const InsufficientSelection = createMessage("Select more than a single token.");
         export const CannotExtractExportedEntity = createMessage("Cannot extract exported declaration");
         export const CannotCombineWritesAndReturns = createMessage("Cannot combine writes and returns");
         export const CannotExtractReadonlyPropertyInitializerOutsideConstructor = createMessage("Cannot move initialization of read-only class property outside of the constructor");
@@ -239,7 +239,7 @@ namespace ts.refactor.extractMethod {
         }
 
         function checkRootNode(node: Node): Diagnostic[] | undefined {
-            if (isIdentifier(node)) {
+            if (isToken(node)) {
                 return [createDiagnosticForNode(node, Messages.InsufficientSelection)];
             }
             return undefined;

tests/cases/fourslash/extract-method-not-for-token.ts

@@ -0,0 +1,6 @@
+/// <reference path='fourslash.ts' />
+
+////"/**/foo";
+
+goTo.marker("");
+verify.not.refactorAvailable('Extract Method');

tests/cases/fourslash/extract-method13.ts

@@ -4,8 +4,8 @@
 // Also checks that we correctly find non-conflicting names in static contexts.
 
 //// class C {
-////     static j = /*c*/100/*d*/;
-////     constructor(q: string = /*a*/"hello"/*b*/) {
+////     static j = /*c*/1 + 1/*d*/;
+////     constructor(q: string = /*a*/"a" + "b"/*b*/) {
 ////     }
 //// }
 
@@ -29,10 +29,10 @@ verify.currentFileContentIs(`class C {
     }
 
     private static newFunction(): string {
-        return "hello";
+        return "a" + "b";
     }
 
     private static newFunction_1() {
-        return 100;
+        return 1 + 1;
     }
 }`);

tests/cases/fourslash/extract-method5.ts

@@ -5,7 +5,7 @@
 // annotation in the extracted function
 
 //// function f() {
-////     var x: 1 | 2 | 3 = /*start*/2/*end*/;
+////     var x: 1 | 2 | 3 = /*start*/1 + 1 === 2 ? 1 : 2/*end*/;
 //// }
 
 goTo.select('start', 'end');
@@ -14,11 +14,12 @@ edit.applyRefactor({
     actionName: "scope_0",
     actionDescription: "Extract function into function 'f'",
 });
+// TODO: GH#18091 (fix formatting to use `2 ? 1 :` and not `2?1:`)
 verify.currentFileContentIs(
 `function f() {
     var x: 1 | 2 | 3 = newFunction();
 
     function newFunction(): 1 | 2 | 3 {
-        return 2;
+        return 1 + 1 === 2?1: 2;
     }
 }`);

tests/cases/fourslash/extract-method7.ts

@@ -3,7 +3,7 @@
 // You cannot extract a function initializer into the function's body.
 // The innermost scope (scope_0) is the sibling of the function, not the function itself.
 
-//// function fn(x = /*a*/3/*b*/) {
+//// function fn(x = /*a*/1 + 1/*b*/) {
 //// }
 
 goTo.select('a', 'b');
@@ -15,6 +15,6 @@ edit.applyRefactor({
 verify.currentFileContentIs(`function fn(x = newFunction()) {
 }
 function newFunction() {
-    return 3;
+    return 1 + 1;
 }
 `);