fix(40469): suggest QF convert 'Convert to named function' to functio…

…n expressions (#40476)
microsoft · Nov 5, 2020 · 899e2d0 · 899e2d0
1 parent 98aaeb7
commit 899e2d0
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Showing 3 changed files with 27 additions and 20 deletions.
diff --git a/src/services/refactors/convertArrowFunctionOrFunctionExpression.ts b/src/services/refactors/convertArrowFunctionOrFunctionExpression.ts
@@ -112,20 +112,20 @@ namespace ts.refactor.convertArrowFunctionOrFunctionExpression {
 
     function getFunctionInfo(file: SourceFile, startPosition: number, program: Program): FunctionInfo | undefined {
         const token = getTokenAtPosition(file, startPosition);
-
-        const arrowFunc = getArrowFunctionFromVariableDeclaration(token.parent);
-        if (arrowFunc && !containingThis(arrowFunc.body)) return { selectedVariableDeclaration: true, func: arrowFunc };
-
-        const maybeFunc = getContainingFunction(token);
         const typeChecker = program.getTypeChecker();
+        const func = tryGetFunctionFromVariableDeclaration(file, typeChecker, token.parent);
+        if (func && !containingThis(func.body)) {
+            return { selectedVariableDeclaration: true, func };
+        }
 
+        const maybeFunc = getContainingFunction(token);
         if (
             maybeFunc &&
             (isFunctionExpression(maybeFunc) || isArrowFunction(maybeFunc)) &&
             !rangeContainsRange(maybeFunc.body, token) &&
             !containingThis(maybeFunc.body)
         ) {
-            if ((isFunctionExpression(maybeFunc) && maybeFunc.name && FindAllReferences.Core.isSymbolReferencedInFile(maybeFunc.name, typeChecker, file))) return undefined;
+            if (isFunctionExpression(maybeFunc) && isFunctionReferencedInFile(file, typeChecker, maybeFunc)) return undefined;
             return { selectedVariableDeclaration: false, func: maybeFunc };
         }
 
@@ -136,13 +136,16 @@ namespace ts.refactor.convertArrowFunctionOrFunctionExpression {
         return isVariableDeclaration(parent) || (isVariableDeclarationList(parent) && parent.declarations.length === 1);
     }
 
-    function getArrowFunctionFromVariableDeclaration(parent: Node): ArrowFunction | undefined {
-        if (!isSingleVariableDeclaration(parent)) return undefined;
-        const variableDeclaration = isVariableDeclaration(parent) ? parent : parent.declarations[0];
-
+    function tryGetFunctionFromVariableDeclaration(sourceFile: SourceFile, typeChecker: TypeChecker, parent: Node): ArrowFunction | FunctionExpression | undefined {
+        if (!isSingleVariableDeclaration(parent)) {
+            return undefined;
+        }
+        const variableDeclaration = isVariableDeclaration(parent) ? parent : first(parent.declarations);
         const initializer = variableDeclaration.initializer;
-        if (!initializer || !isArrowFunction(initializer)) return undefined;
-        return initializer;
+        if (initializer && (isArrowFunction(initializer) || isFunctionExpression(initializer) && !isFunctionReferencedInFile(sourceFile, typeChecker, initializer))) {
+            return initializer;
+        }
+        return undefined;
     }
 
     function convertToBlock(body: ConciseBody): Block {
@@ -213,4 +216,8 @@ namespace ts.refactor.convertArrowFunctionOrFunctionExpression {
     function canBeConvertedToExpression(body: Block, head: Statement): head is ReturnStatement {
         return body.statements.length === 1 && ((isReturnStatement(head) && !!head.expression));
     }
+
+    function isFunctionReferencedInFile(sourceFile: SourceFile, typeChecker: TypeChecker, node: FunctionExpression): boolean {
+        return !!node.name && FindAllReferences.Core.isSymbolReferencedInFile(node.name, typeChecker, sourceFile);
+    }
 }
diff --git a/tests/cases/fourslash/refactorConvertArrowFunctionOrFunctionExpression_Availability_Anon.ts b/tests/cases/fourslash/refactorConvertArrowFunctionOrFunctionExpression_Availability_Anon.ts
@@ -3,14 +3,14 @@
 //// /*z*/c/*y*/onst /*x*/f/*w*/oo = /*v*/f/*u*/unction() /*t*/{/*s*/ /*r*/r/*q*/eturn 42;};
 
 goTo.select("z", "y");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
 verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to anonymous function");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
 
 goTo.select("x", "w");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
 verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to anonymous function");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
 
 goTo.select("v", "u");
 verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to named function");

diff --git a/...ourslash/refactorConvertArrowFunctionOrFunctionExpression_Availability_Anon_unusedName.ts b/...ourslash/refactorConvertArrowFunctionOrFunctionExpression_Availability_Anon_unusedName.ts
@@ -3,14 +3,14 @@
 //// /*z*/c/*y*/onst /*x*/f/*w*/oo = /*v*/f/*u*/unction bar() /*t*/{/*s*/ /*r*/r/*q*/eturn 42;};
 
 goTo.select("z", "y");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
 verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to anonymous function");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
 
 goTo.select("x", "w");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
 verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to anonymous function");
-verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to named function");
+verify.refactorAvailable("Convert arrow function or function expression", "Convert to arrow function");
 
 goTo.select("v", "u");
 verify.not.refactorAvailable("Convert arrow function or function expression", "Convert to named function");