add refactor of extract type

src/compiler/diagnosticMessages.json

@@ -4930,5 +4930,17 @@
     "Convert parameters to destructured object": {
         "category": "Message",
         "code": 95075
+    },
+    "Extract type": {
+        "category": "Message",
+        "code": 95076
+    },
+    "Extract to type alias": {
+        "category": "Message",
+        "code": 95077
+    },
+    "Extract to typedef": {
+        "category": "Message",
+        "code": 95078
     }
 }

src/services/refactors/extractType.ts

@@ -0,0 +1,141 @@
+/* @internal */
+namespace ts.refactor {
+    const refactorName = "Extract type";
+    const extractToTypeAlias = "Extract to type alias";
+    const extractToTypeDef = "Extract to typedef";
+    registerRefactor(refactorName, {
+        getAvailableActions(context): ReadonlyArray<ApplicableRefactorInfo> {
+            const info = getRangeToExtract(context);
+            if (!info) return emptyArray;
+
+            return [{
+                name: refactorName,
+                description: getLocaleSpecificMessage(Diagnostics.Extract_type),
+                actions: [info.isJS ? {
+                    name: extractToTypeDef, description: getLocaleSpecificMessage(Diagnostics.Extract_to_typedef)
+                } : {
+                        name: extractToTypeAlias, description: getLocaleSpecificMessage(Diagnostics.Extract_to_type_alias)
+                    }]
+            }];
+        },
+        getEditsForAction(context, actionName): RefactorEditInfo {
+            Debug.assert(actionName === extractToTypeAlias || actionName === extractToTypeDef);
+            const { file } = context;
+            const info = Debug.assertDefined(getRangeToExtract(context));
+            Debug.assert(actionName === extractToTypeAlias && !info.isJS || actionName === extractToTypeDef && info.isJS);
+
+            const name = getUniqueName("NewType", file);
+            const edits = textChanges.ChangeTracker.with(context, changes => info.isJS ?
+                doTypedefChange(changes, file, name, info.firstStatement, info.selection) :
+                doTypeAliasChange(changes, file, name, info.firstStatement, info.selection, info.typeParameters));
+
+            const renameFilename = file.fileName;
+            const renameLocation = getRenameLocation(edits, renameFilename, name, /*preferLastLocation*/ false);
+            return { edits, renameFilename, renameLocation };
+        }
+    });
+
+    interface TypeAliasInfo { isJS: false; selection: TypeNode; firstStatement: Statement; typeParameters: ReadonlyArray<string>; }
+    interface TypedefInfo { isJS: true; selection: TypeNode; firstStatement: Statement & HasJSDoc; }
+    type Info = TypeAliasInfo | TypedefInfo;
+    function getRangeToExtract(context: RefactorContext): Info | undefined {
+        const { file, startPosition } = context;
+        const isJS = isSourceFileJS(file);
+        const current = getTokenAtPosition(file, startPosition);
+        const range = createTextRangeFromSpan(getRefactorContextSpan(context));
+
+        const selection = findAncestor(current, (node => node.parent && rangeContainsSkipTrivia(range, node, file) && !rangeContainsSkipTrivia(range, node.parent, file)));
+        if (!selection || !isTypeNode(selection)) return undefined;
+
+        if (isJS) {
+            // typeparam tag is not supported yet
+            return {
+                isJS,
+                selection,
+                firstStatement: Debug.assertDefined((findAncestor(selection, isStatementButNotBlockAndHasJSDoc))),
+            };
+        }
+        else {
+            const firstStatement = Debug.assertDefined((findAncestor(selection, isStatementButNotBlock)));
+            const typeParameters = checkAndCollectionTypeArguments(context.program.getTypeChecker(), selection, firstStatement, file);
+            if (!typeParameters) return undefined;
+
+            return { isJS, selection, firstStatement, typeParameters };
+        }
+    }
+
+    function isStatementButNotBlock(n: Node): n is Statement {
+        return n && isStatement(n) && !isBlock(n);
+    }
+
+    function isStatementButNotBlockAndHasJSDoc(n: Node): n is (Statement & HasJSDoc) {
+        return isStatementButNotBlock && hasJSDocNodes(n);
+    }
+
+    function rangeContainsSkipTrivia(r1: TextRange, node: Node, file: SourceFile): boolean {
+        return rangeContainsStartEnd(r1, skipTrivia(file.text, node.pos), node.end);
+    }
+
+    function checkAndCollectionTypeArguments(checker: TypeChecker, selection: TypeNode, statement: Statement, file: SourceFile): string[] | undefined {
+        let hasError = false;
+        const result: string[] = [];
+        visitor(selection);
+        return hasError ? undefined : result;
+
+        function visitor(node: Node) {
+            if (isTypeReferenceNode(node)) {
+                if (isIdentifier(node.typeName)) {
+                    const symbol = checker.resolveName(node.typeName.text, node.typeName, SymbolFlags.TypeParameter, /* excludeGlobals */ true);
+                    if (symbol) {
+                        const declaration = first(symbol.declarations);
+                        if (rangeContainsSkipTrivia(statement, declaration, file) && !rangeContainsSkipTrivia(selection, declaration, file)) {
+                            result.push(node.typeName.text);
+                        }
+                    }
+                }
+            }
+            else if (isInferTypeNode(node)) {
+                const conditionalTypeNode = findAncestor(node, isConditionalTypeNode);
+                if (!conditionalTypeNode || !rangeContainsSkipTrivia(selection, conditionalTypeNode, file)) {
+                    hasError = true;
+                    return;
+                }
+            }
+            else if (isTypePredicateNode(node) && !rangeContainsSkipTrivia(selection, node.parent, file)) {
+                hasError = true;
+                return;
+            }
+            else if (isTypeQueryNode(node) && isIdentifier(node.exprName)) {
+                const symbol = checker.resolveName(node.exprName.text, node.exprName, SymbolFlags.Value, /* excludeGlobals */ false);
+                if (symbol && rangeContainsSkipTrivia(statement, symbol.valueDeclaration, file) && !rangeContainsSkipTrivia(selection, symbol.valueDeclaration, file)) {
+                    hasError = true;
+                    return;
+                }
+            }
+            forEachChild(node, visitor);
+        }
+    }
+
+    function doTypeAliasChange(changes: textChanges.ChangeTracker, file: SourceFile, name: string, firstStatement: Statement, selection: TypeNode, typeParameters: ReadonlyArray<string>) {
+        const newTypeNode = createTypeAliasDeclaration(
+            /* decorators */ undefined,
+            /* monifiers */ undefined,
+            name,
+            typeParameters.map(id => createTypeParameterDeclaration(id)),
+            selection
+        );
+        changes.insertNodeBefore(file, firstStatement, newTypeNode, /* blankLineBetween */ true);
+        changes.replaceNode(file, selection, createTypeReferenceNode(name, typeParameters.map(id => createTypeReferenceNode(id, /* typeArguments */ undefined))));
+    }
+
+    function doTypedefChange(changes: textChanges.ChangeTracker, file: SourceFile, name: string, firstStatement: HasJSDoc, selection: TypeNode) {
+        const node = <JSDocTypedefTag>createNode(SyntaxKind.JSDocTypedefTag);
+        node.tagName = createIdentifier("typedef"); // TODO: jsdoc factory https://github.com/Microsoft/TypeScript/pull/29539
+        node.fullName = createIdentifier(name);
+        node.name = node.fullName;
+        node.typeExpression = createJSDocTypeExpression(selection);
+
+        changes.insertNodeBefore(file, firstStatement, createJSDocComment(/* comment */ undefined, createNodeArray([node])), /* blankLineBetween */ true);
+        changes.replaceNode(file, selection, createTypeReferenceNode(name, /* typeArguments */ undefined));
+    }
+}

src/services/tsconfig.json

@@ -81,6 +81,7 @@
         "refactors/convertExport.ts",
         "refactors/convertImport.ts",
         "refactors/extractSymbol.ts",
+        "refactors/extractType.ts",
         "refactors/generateGetAccessorAndSetAccessor.ts",
         "refactors/moveToNewFile.ts",
         "refactors/addOrRemoveBracesToArrowFunction.ts",

tests/cases/fourslash/refactorExtractType1.ts

@@ -0,0 +1,16 @@
+/// <reference path='fourslash.ts' />
+
+//// var x: /*a*/{ a?: number, b?: string }/*b*/ = { };
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = {
+    a?: number;
+    b?: string;
+};
+
+var x: NewType = { };`,
+});

tests/cases/fourslash/refactorExtractType10.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+//// function foo(a: number, b?: number, ...c: number[]): /*a*/boolean/*b*/ {
+////     return false as boolean
+//// }
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = boolean;
+
+function foo(a: number, b?: number, ...c: number[]): NewType {
+    return false as boolean
+}`,
+});

tests/cases/fourslash/refactorExtractType11.ts

@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+//// function foo(a: number, b?: number, ...c: number[]): boolean {
+////     return false as /*a*/boolean/*b*/
+//// }
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `function foo(a: number, b?: number, ...c: number[]): boolean {
+    type /*RENAME*/NewType = boolean;
+
+    return false as NewType
+}`,
+});

tests/cases/fourslash/refactorExtractType12.ts

@@ -0,0 +1,21 @@
+/// <reference path='fourslash.ts' />
+
+//// interface A<T = /*a*/string/*b*/> {
+////     a: boolean
+////     b: number
+////     c: T
+//// }
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = string;
+
+interface A<T = NewType> {
+    a: boolean
+    b: number
+    c: T
+}`,
+});

tests/cases/fourslash/refactorExtractType13.ts

@@ -0,0 +1,21 @@
+/// <reference path='fourslash.ts' />
+
+//// interface A<T = string> {
+////     a: /*a*/boolean/*b*/
+////     b: number
+////     c: T
+//// }
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = boolean;
+
+interface A<T = string> {
+    a: NewType
+    b: number
+    c: T
+}`,
+});

tests/cases/fourslash/refactorExtractType14.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<T = /*a*/boolean/*b*/> = string | number | T
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = boolean;
+
+type A<T = NewType> = string | number | T`,
+});

tests/cases/fourslash/refactorExtractType15.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<T = boolean> = /*a*/string/*b*/ | number | T
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = string;
+
+type A<T = boolean> = NewType | number | T`,
+});

tests/cases/fourslash/refactorExtractType16.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// var x: { a?: /*a*/number/*b*/, b?: string } = { };
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = number;
+
+var x: { a?: NewType, b?: string } = { };`,
+});

tests/cases/fourslash/refactorExtractType17.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<T = boolean> = string | number | /*a*/T/*b*/
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType<T> = T;
+
+type A<T = boolean> = string | number | NewType<T>`,
+});

tests/cases/fourslash/refactorExtractType18.ts

@@ -0,0 +1,14 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<B, C, D = B> = /*a*/Partial<C | string>/*b*/ & D | C
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType<C> = Partial<C | string>;
+
+type A<B, C, D = B> = NewType<C> & D | C`,
+});
+

tests/cases/fourslash/refactorExtractType19.ts

@@ -0,0 +1,14 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<B, C, D = B> = /*a*/Partial<C | string | D>/*b*/ & D | C
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType<C, D> = Partial<C | string | D>;
+
+type A<B, C, D = B> = NewType<C, D> & D | C`,
+});
+

tests/cases/fourslash/refactorExtractType2.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// var x: /*a*/string/*b*/ = '';
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType = string;
+
+var x: NewType = '';`,
+});

tests/cases/fourslash/refactorExtractType20.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<T, U> = () => <T>(v: /*a*/T/*b*/) => (v: T) => <T>(v: T) => U
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType<T> = T;
+
+type A<T, U> = () => <T>(v: NewType<T>) => (v: T) => <T>(v: T) => U`,
+});

tests/cases/fourslash/refactorExtractType21.ts

@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+
+//// type A<T, U> = () => <T>(v: T) => (v: /*a*/T/*b*/) => <T>(v: T) => U
+
+goTo.select("a", "b");
+edit.applyRefactor({
+    refactorName: "Extract type",
+    actionName: "Extract to type alias",
+    actionDescription: "Extract to type alias",
+    newContent: `type /*RENAME*/NewType<T> = T;
+
+type A<T, U> = () => <T>(v: T) => (v: NewType<T>) => <T>(v: T) => U`,
+});