Migrate Babel from Flow to TypeScript (except Babel parser) (babel#11578

)

Co-authored-by: Nicolò Ribaudo <[email protected]>

.eslintrc.cjs

@@ -84,7 +84,7 @@ module.exports = {
       ],
       excludedFiles: [
         // @babel/register is the require() hook, so it will always be CJS-based
-        "packages/babel-register/**/*.js",
+        "packages/babel-register/**/*.{js,ts}",
       ],
       rules: {
         "no-restricted-globals": ["error", ...cjsGlobals],

Gulpfile.mjs

@@ -61,7 +61,7 @@ function mapSrcToLib(srcPath) {
 function mapToDts(packageName) {
   return packageName.replace(
     /(?<=\\|\/|^)(packages|eslint|codemods)(?=\\|\/)/,
-    "dts"
+    "dts/$1"
   );
 }
 

eslint/babel-eslint-plugin/src/rules/semi.js → eslint/babel-eslint-plugin/src/rules/semi.ts

@@ -47,7 +47,7 @@ function isOneLinerBlock(context, node) {
   );
 }
 
-function report(context, node, missing) {
+function report(context, node, missing?) {
   const lastToken = context.getSourceCode().getLastToken(node);
 
   let message,

packages/babel-core/src/config/plugin.ts

@@ -2,13 +2,13 @@ import type { PluginObject } from "./validation/plugins";
 
 export default class Plugin {
   key: string | undefined | null;
-  manipulateOptions: ((options: unknown, parserOpts: unknown) => void) | void;
-  post: Function | void;
-  pre: Function | void;
+  manipulateOptions?: (options: unknown, parserOpts: unknown) => void;
+  post?: Function;
+  pre?: Function;
   visitor: {};
 
-  parserOverride: Function | void;
-  generatorOverride: Function | void;
+  parserOverride?: Function;
+  generatorOverride?: Function;
 
   options: {};
 

packages/babel-generator/src/buffer.ts

@@ -38,7 +38,7 @@ export default class Buffer {
    * Get the final string output from the buffer, along with the sourcemap if one exists.
    */
 
-  get(): any {
+  get() {
     this._flush();
 
     const map = this._map;

packages/babel-generator/src/generators/jsx.ts

@@ -67,7 +67,7 @@ export function JSXElement(this: Printer, node: t.JSXElement) {
   if (open.selfClosing) return;
 
   this.indent();
-  for (const child of node.children as Array<any>) {
+  for (const child of node.children) {
     this.print(child, node);
   }
   this.dedent();
@@ -109,7 +109,7 @@ export function JSXFragment(this: Printer, node: t.JSXFragment) {
   this.print(node.openingFragment, node);
 
   this.indent();
-  for (const child of node.children as Array<any>) {
+  for (const child of node.children) {
     this.print(child, node);
   }
   this.dedent();

packages/babel-generator/src/generators/statements.ts

@@ -267,7 +267,7 @@ export function VariableDeclaration(
   let hasInits = false;
   // don't add whitespace to loop heads
   if (!isFor(parent)) {
-    for (const declar of node.declarations as Array<any>) {
+    for (const declar of node.declarations) {
       if (declar.init) {
         // has an init so let's split it up over multiple lines
         hasInits = true;

packages/babel-generator/src/index.ts

@@ -246,7 +246,7 @@ export default function generate(
   ast: t.Node,
   opts?: GeneratorOptions,
   code?: string | { [filename: string]: string },
-): any {
+) {
   const gen = new Generator(ast, opts, code);
   return gen.generate();
 }

packages/babel-generator/src/printer.ts

@@ -375,7 +375,7 @@ class Printer {
    *  `undefined` will be returned and not `foo` due to the terminator.
    */
 
-  startTerminatorless(isLabel: boolean = false): any {
+  startTerminatorless(isLabel: boolean = false) {
     if (isLabel) {
       this._noLineTerminator = true;
       return null;

packages/babel-helper-builder-binary-assignment-operator-visitor/src/index.js → packages/babel-helper-builder-binary-assignment-operator-visitor/src/index.ts

@@ -1,15 +1,17 @@
 import explode from "@babel/helper-explode-assignable-expression";
 import { assignmentExpression, sequenceExpression } from "@babel/types";
+import type { Visitor } from "@babel/traverse";
 
-export default function (opts: { build: Function, operator: string }): Object {
+export default function (opts: { build: Function; operator: string }) {
   const { build, operator } = opts;
 
-  return {
+  const visitor: Visitor = {
     AssignmentExpression(path) {
       const { node, scope } = path;
       if (node.operator !== operator + "=") return;
 
       const nodes = [];
+      // @ts-expect-error todo(flow->ts)
       const exploded = explode(node.left, nodes, this, scope);
       nodes.push(
         assignmentExpression(
@@ -28,4 +30,5 @@ export default function (opts: { build: Function, operator: string }): Object {
       }
     },
   };
+  return visitor;
 }

packages/babel-helper-builder-react-jsx/package.json

@@ -17,6 +17,9 @@
     "@babel/helper-annotate-as-pure": "workspace:^",
     "@babel/types": "workspace:^"
   },
+  "devDependencies": {
+    "@babel/traverse": "workspace:^"
+  },
   "engines": {
     "node": ">=6.9.0"
   },

packages/babel-helper-builder-react-jsx/src/index.js → packages/babel-helper-builder-react-jsx/src/index.ts

@@ -24,17 +24,19 @@ import {
   thisExpression,
 } from "@babel/types";
 import annotateAsPure from "@babel/helper-annotate-as-pure";
+import type { Visitor } from "@babel/traverse";
 
 type ElementState = {
-  tagExpr: Object, // tag node
-  tagName: ?string, // raw string tag name
-  args: Array<Object>, // array of call arguments
-  call?: Object, // optional call property that can be set to override the call expression returned
-  pure: boolean, // true if the element can be marked with a #__PURE__ annotation
+  tagExpr: any; // tag node,
+  tagName: string | undefined | null; // raw string tag name,
+  args: Array<any>; // array of call arguments,
+  call?: any; // optional call property that can be set to override the call expression returned,
+  pure: boolean; // true if the element can be marked with a #__PURE__ annotation
+  callee?: any;
 };
 
 export default function (opts) {
-  const visitor = {};
+  const visitor: Visitor = {};
 
   visitor.JSXNamespacedName = function (path) {
     if (opts.throwIfNamespace) {
@@ -81,6 +83,7 @@ You can set \`throwIfNamespace: false\` to bypass this warning.`,
       if (node.name === "this" && isReferenced(node, parent)) {
         return thisExpression();
       } else if (isValidIdentifier(node.name, false)) {
+        // @ts-expect-error todo(flow->ts) avoid type unsafe mutations
         node.type = "Identifier";
       } else {
         return stringLiteral(node.name);
@@ -152,6 +155,7 @@ You can set \`throwIfNamespace: false\` to bypass this warning.`,
     if (isIdentifier(tagExpr)) {
       tagName = tagExpr.name;
     } else if (isLiteral(tagExpr)) {
+      // @ts-expect-error todo(flow->ts) NullLiteral
       tagName = tagExpr.value;
     }
 

packages/babel-helper-create-class-features-plugin/src/index.ts

@@ -19,6 +19,7 @@ import {
   isLoose,
 } from "./features";
 import { assertFieldTransformed } from "./typescript";
+import type { ParserOptions } from "@babel/parser";
 
 export { FEATURES, enableFeature, injectInitialization };
 
@@ -38,7 +39,7 @@ interface Options {
   feature: number;
   loose?: boolean;
   // same as PluginObject.manipulateOptions
-  manipulateOptions: (options: unknown, parserOpts: unknown) => void;
+  manipulateOptions: (options: unknown, parserOpts: ParserOptions) => void;
   // TODO(flow->ts): change to babel api
   api?: { assumption: (key?: string) => boolean | undefined };
 }

packages/babel-helper-define-map/src/index.js → packages/babel-helper-define-map/src/index.ts

@@ -18,7 +18,7 @@ import {
   toKeyAlias,
 } from "@babel/types";
 
-function toKind(node: Object) {
+function toKind(node: any) {
   if (isClassMethod(node) || isObjectMethod(node)) {
     if (node.kind === "get" || node.kind === "set") {
       return node.kind;
@@ -30,18 +30,12 @@ function toKind(node: Object) {
 
 const has = Function.prototype.call.bind(Object.prototype.hasOwnProperty);
 
-export function push(
-  mutatorMap: Object,
-  node: Object,
-  kind: string,
-  file,
-  scope?,
-): Object {
+export function push(mutatorMap: any, node: any, kind: string, file, scope?) {
   const alias = toKeyAlias(node);
 
   //
 
-  let map = {};
+  let map = {} as any;
   if (has(mutatorMap, alias)) map = mutatorMap[alias];
   mutatorMap[alias] = map;
 
@@ -79,6 +73,7 @@ export function push(
   } else if (isObjectMethod(node) || isClassMethod(node)) {
     value = functionExpression(
       null,
+      // @ts-expect-error todo(flow->ts) TSParameterProperty is not assignable to parameter of type 'Identifier | RestElement | Pattern'.
       node.params,
       node.body,
       node.generator,
@@ -110,7 +105,7 @@ export function push(
   return map;
 }
 
-export function hasComputed(mutatorMap: Object): boolean {
+export function hasComputed(mutatorMap: any): boolean {
   for (const key of Object.keys(mutatorMap)) {
     if (mutatorMap[key]._computed) {
       return true;
@@ -119,7 +114,7 @@ export function hasComputed(mutatorMap: Object): boolean {
   return false;
 }
 
-export function toComputedObjectFromClass(obj: Object): Object {
+export function toComputedObjectFromClass(obj: any) {
   const objExpr = arrayExpression([]);
 
   for (let i = 0; i < obj.properties.length; i++) {
@@ -134,7 +129,7 @@ export function toComputedObjectFromClass(obj: Object): Object {
   return objExpr;
 }
 
-export function toClassObject(mutatorMap: Object): Object {
+export function toClassObject(mutatorMap: any) {
   const objExpr = objectExpression([]);
 
   Object.keys(mutatorMap).forEach(function (mutatorMapKey) {
@@ -160,7 +155,7 @@ export function toClassObject(mutatorMap: Object): Object {
   return objExpr;
 }
 
-export function toDefineObject(mutatorMap: Object): Object {
+export function toDefineObject(mutatorMap: any) {
   Object.keys(mutatorMap).forEach(function (key) {
     const map = mutatorMap[key];
     if (map.value) map.writable = booleanLiteral(true);

packages/babel-helper-module-transforms/src/normalize-and-load-metadata.ts

@@ -482,8 +482,7 @@ function getLocalExportMetadata(
       (initializeReexports || !child.node.source)
     ) {
       if (child.node.declaration) {
-        // todo: flow->ts babel-types node field types
-        const declaration = child.get("declaration") as NodePath;
+        const declaration = child.get("declaration");
         const ids = declaration.getOuterBindingIdentifierPaths();
         Object.keys(ids).forEach(name => {
           if (name === "__esModule") {

packages/babel-helper-plugin-utils/src/index.js → packages/babel-helper-plugin-utils/src/index.ts

@@ -1,4 +1,19 @@
-export function declare(builder) {
+export function declare<
+  Args extends
+    | [any]
+    | [any, any?]
+    | [any, any?, any?]
+    | [any, any]
+    | [any, any, any?]
+    | [any, any, any],
+  Builder extends (...args: Args) => any,
+>(
+  builder: Builder,
+  // todo(flow->ts) maybe add stricter type for returned function
+  // reason any is there to not expose exact implementation details in type
+  // example of issue with this packages/babel-preset-typescript/src/index.ts
+): Builder extends (...args: infer A) => any ? (...args: A) => any : never {
+  // @ts-ignore
   return (api, options, dirname) => {
     let clonedApi;
 
@@ -10,6 +25,7 @@ export function declare(builder) {
       clonedApi[name] = apiPolyfills[name](clonedApi);
     }
 
+    // @ts-ignore
     return builder(clonedApi ?? api, options || {}, dirname);
   };
 }
@@ -101,12 +117,9 @@ function throwVersionError(range, version) {
     Error.stackTraceLimit = limit;
   }
 
-  throw Object.assign(
-    err,
-    ({
-      code: "BABEL_VERSION_UNSUPPORTED",
-      version,
-      range,
-    }: any),
-  );
+  throw Object.assign(err, {
+    code: "BABEL_VERSION_UNSUPPORTED",
+    version,
+    range,
+  } as any);
 }

packages/babel-helper-remap-async-to-generator/src/index.js → packages/babel-helper-remap-async-to-generator/src/index.ts

@@ -30,8 +30,11 @@ const awaitVisitor = {
 };
 
 export default function (
-  path: NodePath,
-  helpers: { wrapAsync: Object, wrapAwait: Object },
+  path: NodePath<any>,
+  helpers: {
+    wrapAsync: any;
+    wrapAwait?: any;
+  },
   noNewArrows?: boolean,
 ) {
   path.traverse(awaitVisitor, {