1006 lines
28 KiB
TypeScript
1006 lines
28 KiB
TypeScript
import { declare } from "@babel/helper-plugin-utils";
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import type { NodePath, Visitor, Scope } from "@babel/traverse";
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import { visitor as tdzVisitor } from "./tdz";
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import type { TDZVisitorState } from "./tdz";
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import { traverse, template, types as t } from "@babel/core";
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import type { File } from "@babel/core";
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const DONE = new WeakSet();
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export default declare((api, opts) => {
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api.assertVersion(7);
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const { throwIfClosureRequired = false, tdz: tdzEnabled = false } = opts;
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if (typeof throwIfClosureRequired !== "boolean") {
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throw new Error(`.throwIfClosureRequired must be a boolean, or undefined`);
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}
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if (typeof tdzEnabled !== "boolean") {
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throw new Error(`.tdz must be a boolean, or undefined`);
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}
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return {
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name: "transform-block-scoping",
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visitor: {
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VariableDeclaration(path) {
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const { node, parent, scope } = path;
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if (!isBlockScoped(node)) return;
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convertBlockScopedToVar(path, null, parent, scope, true);
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// @ts-expect-error todo(flow->ts): avoid mutations
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if (node._tdzThis) {
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const nodes: t.Node[] = [node];
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for (let i = 0; i < node.declarations.length; i++) {
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const decl = node.declarations[i];
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const assign = t.assignmentExpression(
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"=",
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t.cloneNode(decl.id),
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decl.init || scope.buildUndefinedNode(),
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);
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// @ts-expect-error todo(flow->ts): avoid mutations
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assign._ignoreBlockScopingTDZ = true;
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nodes.push(t.expressionStatement(assign));
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decl.init = this.addHelper("temporalUndefined");
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}
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// @ts-expect-error todo(flow->ts): avoid mutations
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node._blockHoist = 2;
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if (path.isCompletionRecord()) {
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// ensure we don't break completion record semantics by returning
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// the initialiser of the last declarator
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nodes.push(t.expressionStatement(scope.buildUndefinedNode()));
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}
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path.replaceWithMultiple(nodes);
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}
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},
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Loop(path, state) {
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const { parent, scope } = path;
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path.ensureBlock();
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const blockScoping = new BlockScoping(
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path,
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path.get("body"),
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parent,
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scope,
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throwIfClosureRequired,
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tdzEnabled,
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state,
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);
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const replace = blockScoping.run();
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if (replace) path.replaceWith(replace);
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},
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CatchClause(path, state) {
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const { parent, scope } = path;
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const blockScoping = new BlockScoping(
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null,
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path.get("body"),
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parent,
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scope,
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throwIfClosureRequired,
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tdzEnabled,
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state,
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);
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blockScoping.run();
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},
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"BlockStatement|SwitchStatement|Program"(
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path: NodePath<t.BlockStatement | t.SwitchStatement | t.Program>,
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state,
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) {
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if (!ignoreBlock(path)) {
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const blockScoping = new BlockScoping(
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null,
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path,
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path.parent,
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path.scope,
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throwIfClosureRequired,
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tdzEnabled,
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state,
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);
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blockScoping.run();
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}
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},
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} as Visitor<File>,
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};
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});
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function ignoreBlock(path) {
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return t.isLoop(path.parent) || t.isCatchClause(path.parent);
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}
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const buildRetCheck = template(`
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if (typeof RETURN === "object") return RETURN.v;
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`);
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function isBlockScoped(node) {
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if (!t.isVariableDeclaration(node)) return false;
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if (node[t.BLOCK_SCOPED_SYMBOL]) return true;
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if (node.kind !== "let" && node.kind !== "const") return false;
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return true;
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}
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/**
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* If there is a loop ancestor closer than the closest function, we
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* consider ourselves to be in a loop.
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*/
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function isInLoop(path) {
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const loopOrFunctionParent = path.find(
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path => path.isLoop() || path.isFunction(),
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);
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return loopOrFunctionParent?.isLoop();
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}
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function convertBlockScopedToVar(
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path,
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node,
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parent,
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scope,
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moveBindingsToParent = false,
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) {
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if (!node) {
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node = path.node;
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}
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// https://github.com/babel/babel/issues/255
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if (isInLoop(path) && !t.isFor(parent)) {
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for (let i = 0; i < node.declarations.length; i++) {
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const declar = node.declarations[i];
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declar.init = declar.init || scope.buildUndefinedNode();
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}
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}
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node[t.BLOCK_SCOPED_SYMBOL] = true;
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node.kind = "var";
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// Move bindings from current block scope to function scope.
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if (moveBindingsToParent) {
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const parentScope = scope.getFunctionParent() || scope.getProgramParent();
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for (const name of Object.keys(path.getBindingIdentifiers())) {
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const binding = scope.getOwnBinding(name);
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if (binding) binding.kind = "var";
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scope.moveBindingTo(name, parentScope);
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}
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}
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}
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function isVar(node): node is t.VariableDeclaration {
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return t.isVariableDeclaration(node, { kind: "var" }) && !isBlockScoped(node);
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}
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interface LetReferenceVisitorState extends TDZVisitorState {
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tdzEnabled: boolean;
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loopDepth: number;
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addHelper: (name) => any;
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letReferences: any;
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closurify: boolean;
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}
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const letReferenceBlockVisitor = traverse.visitors.merge([
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{
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Loop: {
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enter(path, state) {
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state.loopDepth++;
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},
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exit(path, state) {
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state.loopDepth--;
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},
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},
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FunctionParent(path, state) {
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// References to block-scoped variables only require added closures if it's
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// possible for the code to run more than once -- otherwise it is safe to
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// simply rename the variables.
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if (state.loopDepth > 0) {
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path.traverse(letReferenceFunctionVisitor, state);
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} else {
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path.traverse(tdzVisitor, state);
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}
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return path.skip();
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},
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},
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tdzVisitor,
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] as Visitor<LetReferenceVisitorState>[]);
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const letReferenceFunctionVisitor = traverse.visitors.merge([
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{
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ReferencedIdentifier(path, state) {
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const ref = state.letReferences.get(path.node.name);
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// not a part of our scope
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if (!ref) return;
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// this scope has a variable with the same name so it couldn't belong
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// to our let scope
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const localBinding = path.scope.getBindingIdentifier(path.node.name);
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if (localBinding && localBinding !== ref) return;
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state.closurify = true;
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},
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},
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tdzVisitor,
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] as Visitor<LetReferenceVisitorState>[]);
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const hoistVarDeclarationsVisitor: Visitor<BlockScoping> = {
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enter(path, self) {
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if (path.isForStatement()) {
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const { node } = path;
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if (isVar(node.init)) {
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const nodes = self.pushDeclar(node.init);
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if (nodes.length === 1) {
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node.init = nodes[0];
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} else {
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node.init = t.sequenceExpression(nodes);
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}
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}
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} else if (path.isForInStatement() || path.isForOfStatement()) {
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const { node } = path;
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if (isVar(node.left)) {
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self.pushDeclar(node.left);
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node.left = node.left.declarations[0].id;
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}
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} else if (isVar(path.node)) {
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path.replaceWithMultiple(
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self.pushDeclar(path.node).map(expr => t.expressionStatement(expr)),
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);
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} else if (path.isFunction()) {
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return path.skip();
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}
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},
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};
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interface LoopVisitorState {
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inSwitchCase: boolean;
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hasBreakContinue: boolean;
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innerLabels: any[];
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hasReturn: boolean;
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ignoreLabeless: boolean;
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LOOP_IGNORE: symbol;
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isLoop: boolean;
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map: any;
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}
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const loopLabelVisitor: Visitor<LoopVisitorState> = {
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LabeledStatement({ node }, state) {
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state.innerLabels.push(node.label.name);
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},
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};
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interface ContinuationVisitorState {
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returnStatements: NodePath<t.ReturnStatement>[];
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reassignments: { [k: string]: boolean | undefined };
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outsideReferences: Map<string, t.Identifier>;
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}
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const continuationVisitor: Visitor<ContinuationVisitorState> = {
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enter(path, state) {
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if (path.isAssignmentExpression() || path.isUpdateExpression()) {
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for (const name of Object.keys(path.getBindingIdentifiers())) {
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if (
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state.outsideReferences.get(name) !==
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path.scope.getBindingIdentifier(name)
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) {
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continue;
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}
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state.reassignments[name] = true;
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}
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} else if (path.isReturnStatement()) {
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state.returnStatements.push(path);
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}
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},
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};
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function loopNodeTo(node) {
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if (t.isBreakStatement(node)) {
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return "break";
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} else if (t.isContinueStatement(node)) {
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return "continue";
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}
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}
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const loopVisitor: Visitor<LoopVisitorState> = {
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Loop(path, state) {
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const oldIgnoreLabeless = state.ignoreLabeless;
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state.ignoreLabeless = true;
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path.traverse(loopVisitor, state);
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state.ignoreLabeless = oldIgnoreLabeless;
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path.skip();
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},
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Function(path) {
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path.skip();
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},
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SwitchCase(path, state) {
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const oldInSwitchCase = state.inSwitchCase;
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state.inSwitchCase = true;
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path.traverse(loopVisitor, state);
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state.inSwitchCase = oldInSwitchCase;
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path.skip();
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},
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"BreakStatement|ContinueStatement|ReturnStatement"(
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path: NodePath<t.BreakStatement | t.ContinueStatement | t.ReturnStatement>,
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state,
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) {
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const { node, scope } = path;
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if (node[this.LOOP_IGNORE]) return;
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let replace;
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let loopText = loopNodeTo(node);
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if (loopText) {
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if (t.isReturnStatement(node)) {
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throw new Error(
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"Internal error: unexpected return statement with `loopText`",
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);
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}
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if (node.label) {
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// we shouldn't be transforming this because it exists somewhere inside
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if (state.innerLabels.indexOf(node.label.name) >= 0) {
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return;
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}
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loopText = `${loopText}|${node.label.name}`;
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} else {
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// we shouldn't be transforming these statements because
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// they don't refer to the actual loop we're scopifying
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if (state.ignoreLabeless) return;
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// break statements mean something different in this context
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if (t.isBreakStatement(node) && state.inSwitchCase) return;
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}
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state.hasBreakContinue = true;
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state.map[loopText] = node;
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replace = t.stringLiteral(loopText);
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}
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if (t.isReturnStatement(node)) {
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state.hasReturn = true;
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replace = t.objectExpression([
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t.objectProperty(
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t.identifier("v"),
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node.argument || scope.buildUndefinedNode(),
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),
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]);
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}
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if (replace) {
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replace = t.returnStatement(replace);
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replace[this.LOOP_IGNORE] = true;
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path.skip();
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path.replaceWith(t.inherits(replace, node));
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}
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},
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};
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function isStrict(path) {
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return !!path.find(({ node }) => {
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if (t.isProgram(node)) {
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if (node.sourceType === "module") return true;
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} else if (!t.isBlockStatement(node)) return false;
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return node.directives.some(
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directive => directive.value.value === "use strict",
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);
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});
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}
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class BlockScoping {
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private parent: any;
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private state: any;
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private scope: Scope;
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private throwIfClosureRequired: boolean;
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private tdzEnabled: boolean;
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private blockPath: NodePath;
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private block: t.Node;
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private outsideLetReferences: Map<string, t.Identifier>;
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private hasLetReferences: boolean;
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private letReferences: any;
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private body: any[];
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// todo(flow->ts) add more specific type
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private loopParent: t.Node;
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private loopLabel: t.Identifier;
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private loopPath: NodePath<t.Loop>;
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private loop: t.Loop;
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private has: any;
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constructor(
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loopPath: NodePath<t.Loop> | undefined | null,
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blockPath: NodePath,
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parent: any,
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scope: Scope,
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throwIfClosureRequired: boolean,
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tdzEnabled: boolean,
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state: any,
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) {
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this.parent = parent;
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this.scope = scope;
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this.state = state;
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this.throwIfClosureRequired = throwIfClosureRequired;
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this.tdzEnabled = tdzEnabled;
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this.blockPath = blockPath;
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this.block = blockPath.node;
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this.outsideLetReferences = new Map();
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this.hasLetReferences = false;
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this.letReferences = new Map();
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this.body = [];
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if (loopPath) {
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this.loopParent = loopPath.parent;
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this.loopLabel =
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t.isLabeledStatement(this.loopParent) && this.loopParent.label;
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this.loopPath = loopPath;
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this.loop = loopPath.node;
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}
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}
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/**
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* Start the ball rolling.
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*/
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run() {
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const block = this.block;
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if (DONE.has(block)) return;
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DONE.add(block);
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const needsClosure = this.getLetReferences();
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this.checkConstants();
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// this is a block within a `Function/Program` so we can safely leave it be
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if (t.isFunction(this.parent) || t.isProgram(this.block)) {
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this.updateScopeInfo();
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return;
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}
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// we can skip everything
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if (!this.hasLetReferences) return;
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if (needsClosure) {
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this.wrapClosure();
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} else {
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this.remap();
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}
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this.updateScopeInfo(needsClosure);
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if (this.loopLabel && !t.isLabeledStatement(this.loopParent)) {
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return t.labeledStatement(this.loopLabel, this.loop);
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}
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}
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checkConstants() {
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const scope = this.scope;
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const state = this.state;
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for (const name of Object.keys(scope.bindings)) {
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const binding = scope.bindings[name];
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if (binding.kind !== "const") continue;
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for (const violation of binding.constantViolations) {
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const readOnlyError = state.addHelper("readOnlyError");
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const throwNode = t.callExpression(readOnlyError, [
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t.stringLiteral(name),
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]);
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if (violation.isAssignmentExpression()) {
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const { operator } = violation.node;
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if (operator === "=") {
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violation.replaceWith(
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t.sequenceExpression([violation.get("right").node, throwNode]),
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);
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} else if (["&&=", "||=", "??="].includes(operator)) {
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violation.replaceWith(
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t.logicalExpression(
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// @ts-expect-error todo(flow->ts)
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operator.slice(0, -1),
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violation.get("left").node,
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t.sequenceExpression([violation.get("right").node, throwNode]),
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),
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);
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} else {
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violation.replaceWith(
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t.sequenceExpression([
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t.binaryExpression(
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// @ts-expect-error todo(flow->ts)
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operator.slice(0, -1),
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violation.get("left").node,
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violation.get("right").node,
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),
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throwNode,
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]),
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);
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}
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} else if (violation.isUpdateExpression()) {
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violation.replaceWith(
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t.sequenceExpression([
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t.unaryExpression("+", violation.get("argument").node),
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throwNode,
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]),
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);
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} else if (violation.isForXStatement()) {
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violation.ensureBlock();
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violation
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.get("left")
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.replaceWith(
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t.variableDeclaration("var", [
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t.variableDeclarator(
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violation.scope.generateUidIdentifier(name),
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),
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]),
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);
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// @ts-expect-error todo(flow->ts): possible bug "for(…) switch(){}"
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violation.node.body.body.unshift(t.expressionStatement(throwNode));
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}
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}
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}
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}
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updateScopeInfo(wrappedInClosure?: boolean) {
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const blockScope = this.blockPath.scope;
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const parentScope =
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blockScope.getFunctionParent() || blockScope.getProgramParent();
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const letRefs = this.letReferences;
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for (const key of letRefs.keys()) {
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const ref = letRefs.get(key);
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const binding = blockScope.getBinding(ref.name);
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if (!binding) continue;
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if (binding.kind === "let" || binding.kind === "const") {
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binding.kind = "var";
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if (wrappedInClosure) {
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if (blockScope.hasOwnBinding(ref.name)) {
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blockScope.removeBinding(ref.name);
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}
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} else {
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blockScope.moveBindingTo(ref.name, parentScope);
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}
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}
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}
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}
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remap() {
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const letRefs = this.letReferences;
|
|
const outsideLetRefs = this.outsideLetReferences;
|
|
const scope = this.scope;
|
|
const blockPathScope = this.blockPath.scope;
|
|
|
|
// alright, so since we aren't wrapping this block in a closure
|
|
// we have to check if any of our let variables collide with
|
|
// those in upper scopes and then if they do, generate a uid
|
|
// for them and replace all references with it
|
|
|
|
for (const key of letRefs.keys()) {
|
|
// just an Identifier node we collected in `getLetReferences`
|
|
// this is the defining identifier of a declaration
|
|
const ref = letRefs.get(key);
|
|
|
|
// todo: could skip this if the colliding binding is in another function
|
|
if (scope.parentHasBinding(key) || scope.hasGlobal(key)) {
|
|
const binding = scope.getOwnBinding(key);
|
|
if (binding) {
|
|
const parentBinding = scope.parent.getOwnBinding(key);
|
|
if (
|
|
binding.kind === "hoisted" &&
|
|
// @ts-expect-error todo(flow->ts)
|
|
!binding.path.node.async &&
|
|
// @ts-expect-error todo(flow->ts)
|
|
!binding.path.node.generator &&
|
|
(!parentBinding || isVar(parentBinding.path.parent)) &&
|
|
!isStrict(binding.path.parentPath)
|
|
) {
|
|
continue;
|
|
}
|
|
// The same identifier might have been bound separately in the block scope and
|
|
// the enclosing scope (e.g. loop or catch statement), so we should handle both
|
|
// individually
|
|
scope.rename(ref.name);
|
|
}
|
|
|
|
if (blockPathScope.hasOwnBinding(key)) {
|
|
blockPathScope.rename(ref.name);
|
|
}
|
|
}
|
|
}
|
|
|
|
for (const key of outsideLetRefs.keys()) {
|
|
const ref = letRefs.get(key);
|
|
// check for collisions with a for loop's init variable and the enclosing scope's bindings
|
|
// https://github.com/babel/babel/issues/8498
|
|
if (isInLoop(this.blockPath) && blockPathScope.hasOwnBinding(key)) {
|
|
blockPathScope.rename(ref.name);
|
|
}
|
|
}
|
|
}
|
|
|
|
wrapClosure() {
|
|
if (this.throwIfClosureRequired) {
|
|
throw this.blockPath.buildCodeFrameError(
|
|
"Compiling let/const in this block would add a closure " +
|
|
"(throwIfClosureRequired).",
|
|
);
|
|
}
|
|
const block = this.block;
|
|
|
|
const outsideRefs = this.outsideLetReferences;
|
|
|
|
// remap loop heads with colliding variables
|
|
if (this.loop) {
|
|
// nb: clone outsideRefs keys since the map is modified within the loop
|
|
for (const name of Array.from(outsideRefs.keys())) {
|
|
const id = outsideRefs.get(name);
|
|
|
|
if (
|
|
this.scope.hasGlobal(id.name) ||
|
|
this.scope.parentHasBinding(id.name)
|
|
) {
|
|
outsideRefs.delete(id.name);
|
|
this.letReferences.delete(id.name);
|
|
|
|
this.scope.rename(id.name);
|
|
|
|
this.letReferences.set(id.name, id);
|
|
outsideRefs.set(id.name, id);
|
|
}
|
|
}
|
|
}
|
|
|
|
// if we're inside of a for loop then we search to see if there are any
|
|
// `break`s, `continue`s, `return`s etc
|
|
this.has = this.checkLoop();
|
|
|
|
// hoist let references to retain scope
|
|
this.hoistVarDeclarations();
|
|
|
|
// turn outsideLetReferences into an array
|
|
const args = Array.from(outsideRefs.values(), node => t.cloneNode(node));
|
|
const params = args.map(id => t.cloneNode(id));
|
|
|
|
const isSwitch = this.blockPath.isSwitchStatement();
|
|
|
|
// build the closure that we're going to wrap the block with, possible wrapping switch(){}
|
|
const fn = t.functionExpression(
|
|
null,
|
|
params,
|
|
// @ts-expect-error todo(flow->ts) improve block type annotations
|
|
t.blockStatement(isSwitch ? [block] : block.body),
|
|
);
|
|
|
|
// continuation
|
|
this.addContinuations(fn);
|
|
|
|
let call: t.CallExpression | t.YieldExpression | t.AwaitExpression =
|
|
t.callExpression(t.nullLiteral(), args);
|
|
let basePath = ".callee";
|
|
|
|
// handle generators
|
|
const hasYield = traverse.hasType(
|
|
fn.body,
|
|
"YieldExpression",
|
|
t.FUNCTION_TYPES,
|
|
);
|
|
if (hasYield) {
|
|
fn.generator = true;
|
|
call = t.yieldExpression(call, true);
|
|
basePath = ".argument" + basePath;
|
|
}
|
|
|
|
// handlers async functions
|
|
const hasAsync = traverse.hasType(
|
|
fn.body,
|
|
"AwaitExpression",
|
|
t.FUNCTION_TYPES,
|
|
);
|
|
if (hasAsync) {
|
|
fn.async = true;
|
|
call = t.awaitExpression(call);
|
|
basePath = ".argument" + basePath;
|
|
}
|
|
|
|
let placeholderPath;
|
|
let index;
|
|
if (this.has.hasReturn || this.has.hasBreakContinue) {
|
|
const ret = this.scope.generateUid("ret");
|
|
|
|
this.body.push(
|
|
t.variableDeclaration("var", [
|
|
t.variableDeclarator(t.identifier(ret), call),
|
|
]),
|
|
);
|
|
placeholderPath = "declarations.0.init" + basePath;
|
|
index = this.body.length - 1;
|
|
|
|
this.buildHas(ret);
|
|
} else {
|
|
this.body.push(t.expressionStatement(call));
|
|
placeholderPath = "expression" + basePath;
|
|
index = this.body.length - 1;
|
|
}
|
|
|
|
let callPath;
|
|
// replace the current block body with the one we're going to build
|
|
if (isSwitch) {
|
|
const { parentPath, listKey, key } = this.blockPath;
|
|
|
|
this.blockPath.replaceWithMultiple(this.body);
|
|
callPath = parentPath.get(listKey)[key + index];
|
|
} else {
|
|
// @ts-expect-error todo(flow->ts) improve block type annotations
|
|
block.body = this.body;
|
|
callPath = this.blockPath.get("body")[index];
|
|
}
|
|
|
|
const placeholder = callPath.get(placeholderPath);
|
|
|
|
let fnPath;
|
|
if (this.loop) {
|
|
const loopId = this.scope.generateUid("loop");
|
|
const p = this.loopPath.insertBefore(
|
|
t.variableDeclaration("var", [
|
|
t.variableDeclarator(t.identifier(loopId), fn),
|
|
]),
|
|
);
|
|
|
|
placeholder.replaceWith(t.identifier(loopId));
|
|
fnPath = p[0].get("declarations.0.init");
|
|
} else {
|
|
placeholder.replaceWith(fn);
|
|
fnPath = placeholder;
|
|
}
|
|
|
|
// Ensure "this", "arguments", and "super" continue to work in the wrapped function.
|
|
fnPath.unwrapFunctionEnvironment();
|
|
}
|
|
|
|
/**
|
|
* If any of the outer let variables are reassigned then we need to rename them in
|
|
* the closure so we can get direct access to the outer variable to continue the
|
|
* iteration with bindings based on each iteration.
|
|
*
|
|
* Reference: https://github.com/babel/babel/issues/1078
|
|
*/
|
|
|
|
addContinuations(fn) {
|
|
const state: ContinuationVisitorState = {
|
|
reassignments: {},
|
|
returnStatements: [],
|
|
outsideReferences: this.outsideLetReferences,
|
|
};
|
|
|
|
this.scope.traverse(fn, continuationVisitor, state);
|
|
|
|
for (let i = 0; i < fn.params.length; i++) {
|
|
const param = fn.params[i];
|
|
if (!state.reassignments[param.name]) continue;
|
|
|
|
const paramName = param.name;
|
|
const newParamName = this.scope.generateUid(param.name);
|
|
fn.params[i] = t.identifier(newParamName);
|
|
|
|
this.scope.rename(paramName, newParamName, fn);
|
|
|
|
state.returnStatements.forEach(returnStatement => {
|
|
returnStatement.insertBefore(
|
|
t.expressionStatement(
|
|
t.assignmentExpression(
|
|
"=",
|
|
t.identifier(paramName),
|
|
t.identifier(newParamName),
|
|
),
|
|
),
|
|
);
|
|
});
|
|
|
|
// assign outer reference as it's been modified internally and needs to be retained
|
|
fn.body.body.push(
|
|
t.expressionStatement(
|
|
t.assignmentExpression(
|
|
"=",
|
|
t.identifier(paramName),
|
|
t.identifier(newParamName),
|
|
),
|
|
),
|
|
);
|
|
}
|
|
}
|
|
|
|
getLetReferences() {
|
|
const block = this.block;
|
|
|
|
const declarators = [];
|
|
|
|
if (this.loop) {
|
|
// @ts-expect-error todo(flow->ts) add check for loop type
|
|
const init = this.loop.left || this.loop.init;
|
|
if (isBlockScoped(init)) {
|
|
declarators.push(init);
|
|
const names = t.getBindingIdentifiers(init);
|
|
for (const name of Object.keys(names)) {
|
|
this.outsideLetReferences.set(name, names[name]);
|
|
}
|
|
}
|
|
}
|
|
|
|
const addDeclarationsFromChild = (path, node) => {
|
|
node = node || path.node;
|
|
if (
|
|
t.isClassDeclaration(node) ||
|
|
t.isFunctionDeclaration(node) ||
|
|
isBlockScoped(node)
|
|
) {
|
|
if (isBlockScoped(node)) {
|
|
convertBlockScopedToVar(path, node, block, this.scope);
|
|
}
|
|
if (node.declarations) {
|
|
for (let i = 0; i < node.declarations.length; i++) {
|
|
declarators.push(node.declarations[i]);
|
|
}
|
|
} else {
|
|
declarators.push(node);
|
|
}
|
|
}
|
|
if (t.isLabeledStatement(node)) {
|
|
addDeclarationsFromChild(path.get("body"), node.body);
|
|
}
|
|
};
|
|
|
|
// @ts-expect-error todo(flow->ts) check block node type instead
|
|
if (block.body) {
|
|
const declarPaths = this.blockPath.get("body");
|
|
// @ts-expect-error todo(flow->ts)
|
|
for (let i = 0; i < block.body.length; i++) {
|
|
// @ts-expect-error todo(flow->ts)
|
|
addDeclarationsFromChild(declarPaths[i]);
|
|
}
|
|
}
|
|
|
|
// @ts-expect-error todo(flow->ts) check block node type instead
|
|
if (block.cases) {
|
|
const declarPaths = this.blockPath.get("cases");
|
|
// @ts-expect-error todo(flow->ts)
|
|
for (let i = 0; i < block.cases.length; i++) {
|
|
// @ts-expect-error todo(flow->ts)
|
|
const consequents = block.cases[i].consequent;
|
|
|
|
for (let j = 0; j < consequents.length; j++) {
|
|
const declar = consequents[j];
|
|
addDeclarationsFromChild(declarPaths[i], declar);
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
for (let i = 0; i < declarators.length; i++) {
|
|
const declar = declarators[i];
|
|
// Passing true as the third argument causes t.getBindingIdentifiers
|
|
// to return only the *outer* binding identifiers of this
|
|
// declaration, rather than (for example) mistakenly including the
|
|
// parameters of a function declaration. Fixes #4880.
|
|
const keys = t.getBindingIdentifiers(declar, false, true);
|
|
for (const key of Object.keys(keys)) {
|
|
this.letReferences.set(key, keys[key]);
|
|
}
|
|
this.hasLetReferences = true;
|
|
}
|
|
|
|
// no let references so we can just quit
|
|
if (!this.hasLetReferences) return;
|
|
|
|
const state: LetReferenceVisitorState = {
|
|
letReferences: this.letReferences,
|
|
closurify: false,
|
|
loopDepth: 0,
|
|
tdzEnabled: this.tdzEnabled,
|
|
addHelper: name => this.state.addHelper(name),
|
|
};
|
|
|
|
if (isInLoop(this.blockPath)) {
|
|
state.loopDepth++;
|
|
}
|
|
|
|
// traverse through this block, stopping on functions and checking if they
|
|
// contain any local let references
|
|
this.blockPath.traverse(letReferenceBlockVisitor, state);
|
|
|
|
return state.closurify;
|
|
}
|
|
|
|
/**
|
|
* If we're inside of a loop then traverse it and check if it has one of
|
|
* the following node types `ReturnStatement`, `BreakStatement`,
|
|
* `ContinueStatement` and replace it with a return value that we can track
|
|
* later on.
|
|
*/
|
|
|
|
checkLoop() {
|
|
const state: LoopVisitorState = {
|
|
hasBreakContinue: false,
|
|
ignoreLabeless: false,
|
|
inSwitchCase: false,
|
|
innerLabels: [],
|
|
hasReturn: false,
|
|
isLoop: !!this.loop,
|
|
map: {},
|
|
LOOP_IGNORE: Symbol(),
|
|
};
|
|
|
|
this.blockPath.traverse(loopLabelVisitor, state);
|
|
this.blockPath.traverse(loopVisitor, state);
|
|
|
|
return state;
|
|
}
|
|
|
|
/**
|
|
* Hoist all let declarations in this block to before it so they retain scope
|
|
* once we wrap everything in a closure.
|
|
*/
|
|
|
|
hoistVarDeclarations() {
|
|
this.blockPath.traverse(hoistVarDeclarationsVisitor, this);
|
|
}
|
|
|
|
/**
|
|
* Turn a `VariableDeclaration` into an array of `AssignmentExpressions` with
|
|
* their declarations hoisted to before the closure wrapper.
|
|
*/
|
|
|
|
pushDeclar(node: t.VariableDeclaration): Array<t.AssignmentExpression> {
|
|
const declars = [];
|
|
const names = t.getBindingIdentifiers(node);
|
|
for (const name of Object.keys(names)) {
|
|
declars.push(t.variableDeclarator(names[name]));
|
|
}
|
|
|
|
this.body.push(t.variableDeclaration(node.kind, declars));
|
|
|
|
const replace = [];
|
|
|
|
for (let i = 0; i < node.declarations.length; i++) {
|
|
const declar = node.declarations[i];
|
|
if (!declar.init) continue;
|
|
|
|
const expr = t.assignmentExpression(
|
|
"=",
|
|
t.cloneNode(declar.id),
|
|
t.cloneNode(declar.init),
|
|
);
|
|
replace.push(t.inherits(expr, declar));
|
|
}
|
|
|
|
return replace;
|
|
}
|
|
|
|
buildHas(ret: string) {
|
|
const body = this.body;
|
|
const has = this.has;
|
|
|
|
if (has.hasBreakContinue) {
|
|
for (const key of Object.keys(has.map)) {
|
|
body.push(
|
|
t.ifStatement(
|
|
t.binaryExpression("===", t.identifier(ret), t.stringLiteral(key)),
|
|
has.map[key],
|
|
),
|
|
);
|
|
}
|
|
}
|
|
|
|
// typeof ret === "object"
|
|
if (has.hasReturn) {
|
|
body.push(
|
|
buildRetCheck({
|
|
RETURN: t.identifier(ret),
|
|
}),
|
|
);
|
|
}
|
|
}
|
|
}
|