Add refactor to convert namespace to named imports and back (#24469)

* Add refactor to convert namespace to named imports and back

* Add tests and comments

* Code review

* Handle shorthand property assignment and re-export

* Don't use forEachFreeIdentifier

* Fix rename after "."

src/compiler/diagnosticMessages.json

@@ -4293,5 +4293,13 @@
     "Convert '{0}' to mapped object type": {
         "category": "Message",
         "code": 95055
+    },
+    "Convert namespace import to named imports": {
+        "category": "Message",
+        "code": 95056
+    },
+    "Convert named imports to namespace import": {
+        "category": "Message",
+        "code": 95057
     }
 }

src/compiler/utilities.ts

@@ -223,11 +223,11 @@ namespace ts {
     }
 
     /**
-     * Returns a value indicating whether a name is unique globally or within the current file
+     * Returns a value indicating whether a name is unique globally or within the current file.
+     * Note: This does not consider whether a name appears as a free identifier or not, so at the expression `x.y` this includes both `x` and `y`.
      */
-    export function isFileLevelUniqueName(currentSourceFile: SourceFile, name: string, hasGlobalName?: PrintHandlers["hasGlobalName"]): boolean {
-        return !(hasGlobalName && hasGlobalName(name))
-            && !currentSourceFile.identifiers.has(name);
+    export function isFileLevelUniqueName(sourceFile: SourceFile, name: string, hasGlobalName?: PrintHandlers["hasGlobalName"]): boolean {
+        return !(hasGlobalName && hasGlobalName(name)) && !sourceFile.identifiers.has(name);
     }
 
     // Returns true if this node is missing from the actual source code. A 'missing' node is different

src/harness/tsconfig.json

@@ -120,6 +120,7 @@
         "../services/codefixes/useDefaultImport.ts",
         "../services/codefixes/fixAddModuleReferTypeMissingTypeof.ts",
         "../services/codefixes/convertToMappedObjectType.ts",
+        "../services/refactors/convertImport.ts",
         "../services/refactors/extractSymbol.ts",
         "../services/refactors/generateGetAccessorAndSetAccessor.ts",
         "../services/refactors/moveToNewFile.ts",

src/server/tsconfig.json

@@ -116,6 +116,7 @@
         "../services/codefixes/useDefaultImport.ts",
         "../services/codefixes/fixAddModuleReferTypeMissingTypeof.ts",
         "../services/codefixes/convertToMappedObjectType.ts",
+        "../services/refactors/convertImport.ts",
         "../services/refactors/extractSymbol.ts",
         "../services/refactors/generateGetAccessorAndSetAccessor.ts",
         "../services/refactors/moveToNewFile.ts",

src/server/tsconfig.library.json

@@ -122,6 +122,7 @@
         "../services/codefixes/useDefaultImport.ts",
         "../services/codefixes/fixAddModuleReferTypeMissingTypeof.ts",
         "../services/codefixes/convertToMappedObjectType.ts",
+        "../services/refactors/convertImport.ts",
         "../services/refactors/extractSymbol.ts",
         "../services/refactors/generateGetAccessorAndSetAccessor.ts",
         "../services/refactors/moveToNewFile.ts",

src/services/codefixes/convertToEs6Module.ts

@@ -437,22 +437,28 @@ namespace ts.codefix {
     type FreeIdentifiers = ReadonlyMap<ReadonlyArray<Identifier>>;
     function collectFreeIdentifiers(file: SourceFile): FreeIdentifiers {
         const map = createMultiMap<Identifier>();
-        file.forEachChild(function recur(node) {
-            if (isIdentifier(node) && isFreeIdentifier(node)) {
-                map.add(node.text, node);
-            }
-            node.forEachChild(recur);
-        });
+        forEachFreeIdentifier(file, id => map.add(id.text, id));
         return map;
     }
 
+    /**
+     * A free identifier is an identifier that can be accessed through name lookup as a local variable.
+     * In the expression `x.y`, `x` is a free identifier, but `y` is not.
+     */
+    function forEachFreeIdentifier(node: Node, cb: (id: Identifier) => void): void {
+        if (isIdentifier(node) && isFreeIdentifier(node)) cb(node);
+        node.forEachChild(child => forEachFreeIdentifier(child, cb));
+    }
+
     function isFreeIdentifier(node: Identifier): boolean {
         const { parent } = node;
         switch (parent.kind) {
             case SyntaxKind.PropertyAccessExpression:
                 return (parent as PropertyAccessExpression).name !== node;
             case SyntaxKind.BindingElement:
                 return (parent as BindingElement).propertyName !== node;
+            case SyntaxKind.ImportSpecifier:
+                return (parent as ImportSpecifier).propertyName !== node;
             default:
                 return true;
         }

src/services/findAllReferences.ts

@@ -712,16 +712,23 @@ namespace ts.FindAllReferences.Core {
     }
 
     /** Used as a quick check for whether a symbol is used at all in a file (besides its definition). */
-    export function isSymbolReferencedInFile(definition: Identifier, checker: TypeChecker, sourceFile: SourceFile) {
+    export function isSymbolReferencedInFile(definition: Identifier, checker: TypeChecker, sourceFile: SourceFile): boolean {
+        return eachSymbolReferenceInFile(definition, checker, sourceFile, () => true) || false;
+    }
+
+    export function eachSymbolReferenceInFile<T>(definition: Identifier, checker: TypeChecker, sourceFile: SourceFile, cb: (token: Identifier) => T): T | undefined {
         const symbol = checker.getSymbolAtLocation(definition);
-        if (!symbol) return true; // Be lenient with invalid code.
-        return getPossibleSymbolReferenceNodes(sourceFile, symbol.name).some(token => {
-            if (!isIdentifier(token) || token === definition || token.escapedText !== definition.escapedText) return false;
-            const referenceSymbol = checker.getSymbolAtLocation(token)!;
-            return referenceSymbol === symbol
+        if (!symbol) return undefined;
+        for (const token of getPossibleSymbolReferenceNodes(sourceFile, symbol.name)) {
+            if (!isIdentifier(token) || token === definition || token.escapedText !== definition.escapedText) continue;
+            const referenceSymbol: Symbol = checker.getSymbolAtLocation(token)!; // See GH#19955 for why the type annotation is necessary
+            if (referenceSymbol === symbol
                 || checker.getShorthandAssignmentValueSymbol(token.parent) === symbol
-                || isExportSpecifier(token.parent) && getLocalSymbolForExportSpecifier(token, referenceSymbol, token.parent, checker) === symbol;
-        });
+                || isExportSpecifier(token.parent) && getLocalSymbolForExportSpecifier(token, referenceSymbol, token.parent, checker) === symbol) {
+                const res = cb(token);
+                if (res) return res;
+            }
+        }
     }
 
     function getPossibleSymbolReferenceNodes(sourceFile: SourceFile, symbolName: string, container: Node = sourceFile): ReadonlyArray<Node> {

src/services/refactors/convertImport.ts

@@ -0,0 +1,130 @@
+/* @internal */
+namespace ts.refactor.generateGetAccessorAndSetAccessor {
+    const refactorName = "Convert import";
+    const actionNameNamespaceToNamed = "Convert namespace import to named imports";
+    const actionNameNamedToNamespace = "Convert named imports to namespace import";
+    registerRefactor(refactorName, {
+        getAvailableActions(context): ApplicableRefactorInfo[] | undefined {
+            const i = getImportToConvert(context);
+            if (!i) return undefined;
+            const description = i.kind === SyntaxKind.NamespaceImport ? Diagnostics.Convert_namespace_import_to_named_imports.message : Diagnostics.Convert_named_imports_to_namespace_import.message;
+            const actionName = i.kind === SyntaxKind.NamespaceImport ? actionNameNamespaceToNamed : actionNameNamedToNamespace;
+            return [{ name: refactorName, description, actions: [{ name: actionName, description }] }];
+        },
+        getEditsForAction(context, actionName): RefactorEditInfo {
+            Debug.assert(actionName === actionNameNamespaceToNamed || actionName === actionNameNamedToNamespace);
+            const edits = textChanges.ChangeTracker.with(context, t => doChange(context.file, context.program, t, Debug.assertDefined(getImportToConvert(context))));
+            return { edits, renameFilename: undefined, renameLocation: undefined };
+        }
+    });
+
+    // Can convert imports of the form `import * as m from "m";` or `import d, { x, y } from "m";`.
+    function getImportToConvert(context: RefactorContext): NamedImportBindings | undefined {
+        const { file } = context;
+        const span = getRefactorContextSpan(context);
+        const token = getTokenAtPosition(file, span.start, /*includeJsDocComment*/ false);
+        const importDecl = getParentNodeInSpan(token, file, span);
+        if (!importDecl || !isImportDeclaration(importDecl)) return undefined;
+        const { importClause } = importDecl;
+        return importClause && importClause.namedBindings;
+    }
+
+    function doChange(sourceFile: SourceFile, program: Program, changes: textChanges.ChangeTracker, toConvert: NamedImportBindings): void {
+        const checker = program.getTypeChecker();
+        if (toConvert.kind === SyntaxKind.NamespaceImport) {
+            doChangeNamespaceToNamed(sourceFile, checker, changes, toConvert, getAllowSyntheticDefaultImports(program.getCompilerOptions()));
+        }
+        else {
+            doChangeNamedToNamespace(sourceFile, checker, changes, toConvert);
+        }
+    }
+
+    function doChangeNamespaceToNamed(sourceFile: SourceFile, checker: TypeChecker, changes: textChanges.ChangeTracker, toConvert: NamespaceImport, allowSyntheticDefaultImports: boolean): void {
+        let usedAsNamespaceOrDefault = false;
+
+        const nodesToReplace: PropertyAccessExpression[] = [];
+        const conflictingNames = createMap<true>();
+
+        FindAllReferences.Core.eachSymbolReferenceInFile(toConvert.name, checker, sourceFile, id => {
+            if (!isPropertyAccessExpression(id.parent)) {
+                usedAsNamespaceOrDefault = true;
+            }
+            else {
+                const parent = cast(id.parent, isPropertyAccessExpression);
+                const exportName = parent.name.text;
+                if (checker.resolveName(exportName, id, SymbolFlags.All, /*excludeGlobals*/ true)) {
+                    conflictingNames.set(exportName, true);
+                }
+                Debug.assert(parent.expression === id);
+                nodesToReplace.push(parent);
+            }
+        });
+
+        // We may need to change `mod.x` to `_x` to avoid a name conflict.
+        const exportNameToImportName = createMap<string>();
+
+        for (const propertyAccess of nodesToReplace) {
+            const exportName = propertyAccess.name.text;
+            let importName = exportNameToImportName.get(exportName);
+            if (importName === undefined) {
+                exportNameToImportName.set(exportName, importName = conflictingNames.has(exportName) ? getUniqueName(exportName, sourceFile) : exportName);
+            }
+            changes.replaceNode(sourceFile, propertyAccess, createIdentifier(importName));
+        }
+
+        const importSpecifiers: ImportSpecifier[] = [];
+        exportNameToImportName.forEach((name, propertyName) => {
+            importSpecifiers.push(createImportSpecifier(name === propertyName ? undefined : createIdentifier(propertyName), createIdentifier(name)));
+        });
+
+        const importDecl = toConvert.parent.parent;
+        if (usedAsNamespaceOrDefault && !allowSyntheticDefaultImports) {
+            // Need to leave the namespace import alone
+            changes.insertNodeAfter(sourceFile, importDecl, updateImport(importDecl, /*defaultImportName*/ undefined, importSpecifiers));
+        }
+        else {
+            changes.replaceNode(sourceFile, importDecl, updateImport(importDecl, usedAsNamespaceOrDefault ? createIdentifier(toConvert.name.text) : undefined, importSpecifiers));
+        }
+    }
+
+    function doChangeNamedToNamespace(sourceFile: SourceFile, checker: TypeChecker, changes: textChanges.ChangeTracker, toConvert: NamedImports): void {
+        const importDecl = toConvert.parent.parent;
+        const { moduleSpecifier } = importDecl;
+
+        const preferredName = moduleSpecifier && isStringLiteral(moduleSpecifier) ? codefix.moduleSpecifierToValidIdentifier(moduleSpecifier.text, ScriptTarget.ESNext) : "module";
+        const namespaceNameConflicts = toConvert.elements.some(element =>
+            FindAllReferences.Core.eachSymbolReferenceInFile(element.name, checker, sourceFile, id =>
+                !!checker.resolveName(preferredName, id, SymbolFlags.All, /*excludeGlobals*/ true)) || false);
+        const namespaceImportName = namespaceNameConflicts ? getUniqueName(preferredName, sourceFile) : preferredName;
+
+        const neededNamedImports: ImportSpecifier[] = [];
+
+        for (const element of toConvert.elements) {
+            const propertyName = (element.propertyName || element.name).text;
+            FindAllReferences.Core.eachSymbolReferenceInFile(element.name, checker, sourceFile, id => {
+                const access = createPropertyAccess(createIdentifier(namespaceImportName), propertyName);
+                if (isShorthandPropertyAssignment(id.parent)) {
+                    changes.replaceNode(sourceFile, id.parent, createPropertyAssignment(id.text, access));
+                }
+                else if (isExportSpecifier(id.parent) && !id.parent.propertyName) {
+                    if (!neededNamedImports.some(n => n.name === element.name)) {
+                        neededNamedImports.push(createImportSpecifier(element.propertyName && createIdentifier(element.propertyName.text), createIdentifier(element.name.text)));
+                    }
+                }
+                else {
+                    changes.replaceNode(sourceFile, id, access);
+                }
+            });
+        }
+
+        changes.replaceNode(sourceFile, toConvert, createNamespaceImport(createIdentifier(namespaceImportName)));
+        if (neededNamedImports.length) {
+            changes.insertNodeAfter(sourceFile, toConvert.parent.parent, updateImport(importDecl, /*defaultImportName*/ undefined, neededNamedImports));
+        }
+    }
+
+    function updateImport(old: ImportDeclaration, defaultImportName: Identifier | undefined, elements: ReadonlyArray<ImportSpecifier> | undefined): ImportDeclaration {
+        return createImportDeclaration(/*decorators*/ undefined, /*modifiers*/ undefined,
+            createImportClause(defaultImportName, elements && elements.length ? createNamedImports(elements) : undefined), old.moduleSpecifier);
+    }
+}

src/services/refactors/extractSymbol.ts

@@ -718,7 +718,7 @@ namespace ts.refactor.extractSymbol {
 
         // Make a unique name for the extracted function
         const file = scope.getSourceFile();
-        const functionNameText = getUniqueName(isClassLike(scope) ? "newMethod" : "newFunction", file.text);
+        const functionNameText = getUniqueName(isClassLike(scope) ? "newMethod" : "newFunction", file);
         const isJS = isInJavaScriptFile(scope);
 
         const functionName = createIdentifier(functionNameText);
@@ -1005,7 +1005,7 @@ namespace ts.refactor.extractSymbol {
 
         // Make a unique name for the extracted variable
         const file = scope.getSourceFile();
-        const localNameText = getUniqueName(isClassLike(scope) ? "newProperty" : "newLocal", file.text);
+        const localNameText = getUniqueName(isClassLike(scope) ? "newProperty" : "newLocal", file);
         const isJS = isInJavaScriptFile(scope);
 
         const variableType = isJS || !checker.isContextSensitive(node)
@@ -1744,23 +1744,6 @@ namespace ts.refactor.extractSymbol {
         }
     }
 
-    function getParentNodeInSpan(node: Node | undefined, file: SourceFile, span: TextSpan): Node | undefined {
-        if (!node) return undefined;
-
-        while (node.parent) {
-            if (isSourceFile(node.parent) || !spanContainsNode(span, node.parent, file)) {
-                return node;
-            }
-
-            node = node.parent;
-        }
-    }
-
-    function spanContainsNode(span: TextSpan, node: Node, file: SourceFile): boolean {
-        return textSpanContainsPosition(span, node.getStart(file)) &&
-            node.getEnd() <= textSpanEnd(span);
-    }
-
     /**
      * Computes whether or not a node represents an expression in a position where it could
      * be extracted.

src/services/refactors/generateGetAccessorAndSetAccessor.ts

@@ -129,8 +129,8 @@ namespace ts.refactor.generateGetAccessorAndSetAccessor {
 
         const name = declaration.name.text;
         const startWithUnderscore = startsWithUnderscore(name);
-        const fieldName = createPropertyName(startWithUnderscore ? name : getUniqueName(`_${name}`, file.text), declaration.name);
-        const accessorName = createPropertyName(startWithUnderscore ? getUniqueName(name.substring(1), file.text) : name, declaration.name);
+        const fieldName = createPropertyName(startWithUnderscore ? name : getUniqueName(`_${name}`, file), declaration.name);
+        const accessorName = createPropertyName(startWithUnderscore ? getUniqueName(name.substring(1), file) : name, declaration.name);
         return {
             isStatic: hasStaticModifier(declaration),
             isReadonly: hasReadonlyModifier(declaration),

src/services/tsconfig.json

@@ -113,6 +113,7 @@
         "codefixes/useDefaultImport.ts",
         "codefixes/fixAddModuleReferTypeMissingTypeof.ts",
         "codefixes/convertToMappedObjectType.ts",
+        "refactors/convertImport.ts",
         "refactors/extractSymbol.ts",
         "refactors/generateGetAccessorAndSetAccessor.ts",
         "refactors/moveToNewFile.ts",

src/services/utilities.ts

@@ -1345,6 +1345,23 @@ namespace ts {
             return forEachEntry(this.map, pred) || false;
         }
     }
+
+    export function getParentNodeInSpan(node: Node | undefined, file: SourceFile, span: TextSpan): Node | undefined {
+        if (!node) return undefined;
+
+        while (node.parent) {
+            if (isSourceFile(node.parent) || !spanContainsNode(span, node.parent, file)) {
+                return node;
+            }
+
+            node = node.parent;
+        }
+    }
+
+    function spanContainsNode(span: TextSpan, node: Node, file: SourceFile): boolean {
+        return textSpanContainsPosition(span, node.getStart(file)) &&
+            node.getEnd() <= textSpanEnd(span);
+    }
 }
 
 // Display-part writer helpers
@@ -1646,9 +1663,9 @@ namespace ts {
     }
 
     /* @internal */
-    export function getUniqueName(baseName: string, fileText: string): string {
+    export function getUniqueName(baseName: string, sourceFile: SourceFile): string {
         let nameText = baseName;
-        for (let i = 1; stringContains(fileText, nameText); i++) {
+        for (let i = 1; !isFileLevelUniqueName(sourceFile, nameText); i++) {
             nameText = `${baseName}_${i}`;
         }
         return nameText;
@@ -1667,7 +1684,7 @@ namespace ts {
             Debug.assert(fileName === renameFilename);
             for (const change of textChanges) {
                 const { span, newText } = change;
-                const index = newText.indexOf(name);
+                const index = indexInTextChange(newText, name);
                 if (index !== -1) {
                     lastPos = span.start + delta + index;
 
@@ -1685,4 +1702,13 @@ namespace ts {
         Debug.assert(lastPos >= 0);
         return lastPos;
     }
+
+    function indexInTextChange(change: string, name: string): number {
+        if (startsWith(change, name)) return 0;
+        // Add a " " to avoid references inside words
+        let idx = change.indexOf(" " + name);
+        if (idx === -1) idx = change.indexOf("." + name);
+        if (idx === -1) idx = change.indexOf('"' + name);
+        return idx === -1 ? -1 : idx + 1;
+    }
 }

tests/cases/fourslash/extract-method-uniqueName.ts

@@ -1,6 +1,6 @@
 /// <reference path='fourslash.ts' />
 
-////// newFunction
+////const newFunction = 0;
 /////*start*/1 + 1/*end*/;
 
 goTo.select('start', 'end')
@@ -9,7 +9,7 @@ edit.applyRefactor({
     actionName: "function_scope_0",
     actionDescription: "Extract to function in global scope",
     newContent:
-`// newFunction
+`const newFunction = 0;
 /*RENAME*/newFunction_1();
 
 function newFunction_1() {