fix(es/jest): Handle @jest/globals (#8994)

**Description:** - We have two `jest` pass. One in `@swc/core` (via _hidden.jest flag), and one in the plugin. This PR fixes only the core one. However, the linked issue is wrong because the code tries to break the rules of ESM specification. So, although this PR closes the issue, the final form is not the issue the author wanted. **Related issue:** - Closes swc-project/plugins#310

Author: kdy1

crates/swc/tests/fixture/jest/mock-globals/input/.swcrc

@@ -0,0 +1,23 @@
+{
+ "$schema": "https://json.schemastore.org/swcrc",
+ "jsc": {
+ "parser": {
+ "syntax": "typescript",
+ "tsx": true,
+ "dynamicImport": true
+ },
+ "transform": {
+ "react": {
+ "runtime": "automatic"
+ }
+ },
+ "baseUrl": "./",
+ "target": "es2021",
+ "keepClassNames": true
+ },
+ "isModule": true,
+ "module": {
+ "type": "commonjs",
+ "ignoreDynamic": false
+ }
+}

crates/swc/tests/fixture/jest/mock-globals/input/1.js

@@ -0,0 +1,17 @@
+
+import { setTimeout } from 'timers/promises';
+
+import { describe, expect, it, jest } from '@jest/globals';
+
+jest.mock('timers/promises', () => ({
+ setTimeout: jest.fn(() => Promise.resolve())
+}));
+
+describe('suite', () => {
+ it('my-test', () => {
+ const totalDelay = jest
+ .mocked(setTimeout)
+ .mock.calls.reduce((agg, call) => agg + (call[0] as number), 0);
+ expect(totalDelay).toStrictEqual(0);
+ })
+})

crates/swc/tests/fixture/jest/mock-globals/output/1.js

@@ -0,0 +1,15 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", {
+ value: true
+});
+const _promises = require("node:timers/promises");
+const _globals = require("@jest/globals");
+_globals.jest.mock('timers/promises', ()=>({
+ setTimeout: _globals.jest.fn(()=>Promise.resolve())
+ }));
+(0, _globals.describe)('suite', ()=>{
+ (0, _globals.it)('my-test', ()=>{
+ const totalDelay = _globals.jest.mocked(_promises.setTimeout).mock.calls.reduce((agg, call)=>agg + call[0], 0);
+ (0, _globals.expect)(totalDelay).toStrictEqual(0);
+ });
+});

crates/swc_ecma_ast/src/module_decl.rs

@@ -1,4 +1,5 @@
 use is_macro::Is;
+use swc_atoms::Atom;
 use swc_common::{ast_node, util::take::Take, EqIgnoreSpan, Span, DUMMY_SP};
 
 use crate::{
@@ -313,3 +314,13 @@ pub enum ModuleExportName {
  #[tag("StringLiteral")]
  Str(Str),
 }
+
+impl ModuleExportName {
+ /// Get the atom of the export name.
+ pub fn atom(&self) -> &Atom {
+ match self {
+ ModuleExportName::Ident(i) => &i.sym,
+ ModuleExportName::Str(s) => &s.value,
+ }
+ }
+}

crates/swc_ecma_ext_transforms/src/jest.rs

@@ -13,10 +13,13 @@ static HOIST_METHODS: phf::Set<&str> = phf_set![
 ];
 
 pub fn jest() -> impl Fold + VisitMut {
- as_folder(Jest)
+ as_folder(Jest::default())
 }
 
-struct Jest;
+#[derive(Default)]
+struct Jest {
+ imported: Vec<Id>,
+}
 
 impl Jest {
  fn visit_mut_stmt_like<T>(&mut self, orig: &mut Vec<T>)
@@ -38,21 +41,13 @@ impl Jest {
  Expr::Call(CallExpr {
  callee: Callee::Expr(callee),
  ..
- }) => match &**callee {
- Expr::Member(
- callee @ MemberExpr {
- prop: MemberProp::Ident(prop),
- ..
- },
- ) => {
- if is_jest(&callee.obj) && HOIST_METHODS.contains(&*prop.sym) {
- hoisted.push(T::from_stmt(stmt))
- } else {
- new.push(T::from_stmt(stmt));
- }
+ }) => {
+ if self.should_hoist(callee) {
+ hoisted.push(T::from_stmt(stmt))
+ } else {
+ new.push(T::from_stmt(stmt))
  }
- _ => new.push(T::from_stmt(stmt)),
- },
+ }
  _ => new.push(T::from_stmt(stmt)),
  },
 
@@ -66,12 +61,63 @@ impl Jest {
 
  *orig = new;
  }
+
+ fn should_hoist(&self, e: &Expr) -> bool {
+ match e {
+ Expr::Ident(i) => self.imported.iter().any(|imported| *imported == i.to_id()),
+
+ Expr::Member(
+ callee @ MemberExpr {
+ prop: MemberProp::Ident(prop),
+ ..
+ },
+ ) => is_global_jest(&callee.obj) && HOIST_METHODS.contains(&*prop.sym),
+
+ _ => false,
+ }
+ }
 }
 
 impl VisitMut for Jest {
  noop_visit_mut_type!();
 
  fn visit_mut_module_items(&mut self, items: &mut Vec<ModuleItem>) {
+ for item in items.iter() {
+ if let ModuleItem::ModuleDecl(ModuleDecl::Import(ImportDecl {
+ specifiers, src, ..
+ })) = item
+ {
+ if src.value == "@jest/globals" {
+ for s in specifiers {
+ match s {
+ ImportSpecifier::Named(ImportNamedSpecifier {
+ local,
+ imported: None,
+ is_type_only: false,
+ ..
+ }) => {
+ if HOIST_METHODS.contains(&*local.sym) {
+ self.imported.push(local.to_id());
+ }
+ }
+
+ ImportSpecifier::Named(ImportNamedSpecifier {
+ local,
+ imported: Some(exported),
+ is_type_only: false,
+ ..
+ }) => {
+ if HOIST_METHODS.contains(exported.atom()) {
+ self.imported.push(local.to_id());
+ }
+ }
+ _ => {}
+ }
+ }
+ }
+ }
+ }
+
  self.visit_mut_stmt_like(items)
  }
 
@@ -80,14 +126,14 @@ impl VisitMut for Jest {
  }
 }
 
-fn is_jest(e: &Expr) -> bool {
+fn is_global_jest(e: &Expr) -> bool {
  match e {
  Expr::Ident(i) => i.sym == *"jest",
- Expr::Member(MemberExpr { obj, .. }) => is_jest(obj),
+ Expr::Member(MemberExpr { obj, .. }) => is_global_jest(obj),
  Expr::Call(CallExpr {
  callee: Callee::Expr(callee),
  ..
- }) => is_jest(callee),
+ }) => is_global_jest(callee),
  _ => false,
  }
 }