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Move module.exports assigment to the top
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When using cjs format make sure to move `module.exports` to the top of
the generated chunk, right after the `__export()` call:

    var exports = {};
    __export(exports, {
      // ...
    });
    module.exports = __toCommonJS(exports);

This guarantees that all circular requires following these calls would
see the correct `module.exports` object.

Additionally, add an extra argument for `__reExport` to copy the data to
the `module.exports`:

    __reExport(exports, module.exports, ...)

This is required to support `export * from '..'` since now
`module.exports` wouldn't automatically receive properties otherwise.

Fix: evanw#1894
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@indutny
indutny committed Feb 26, 2022
1 parent f93f488 commit 78a7a5e
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Showing 6 changed files with 71 additions and 53 deletions.
63 changes: 41 additions & 22 deletions internal/bundler/linker.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2024,6 +2024,32 @@ func (c *linkerContext) createExportsForFile(sourceIndex uint32) {
repr.AST.UsesExportsRef = true
}

// Decorate "module.exports" with the "__esModule" flag to indicate that
// we used to be an ES module. This is done by wrapping the exports object
// instead of by mutating the exports object because other modules in the
// bundle (including the entry point module) may do "import * as" to get
// access to the exports object and should NOT see the "__esModule" flag.
if repr.Meta.NeedsExportsVariable &&
repr.Meta.ForceIncludeExportsForEntryPoint &&
c.options.OutputFormat == config.FormatCommonJS {

runtimeRepr := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr)
toCommonJSRef := runtimeRepr.AST.NamedExports["__toCommonJS"].Ref

// "module.exports = __toCommonJS(exports);"
nsExportStmts = append(nsExportStmts, js_ast.AssignStmt(
js_ast.Expr{Data: &js_ast.EDot{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.unboundModuleRef}},
Name: "exports",
}},

js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: toCommonJSRef}},
Args: []js_ast.Expr{{Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}}},
}},
))
}

// No need to generate a part if it'll be empty
if len(nsExportStmts) > 0 {
// Initialize the part that was allocated for us earlier. The information
Expand Down Expand Up @@ -3492,6 +3518,16 @@ func (c *linkerContext) convertStmtsForChunk(sourceIndex uint32, stmtList *stmtL
repr := file.InputFile.Repr.(*graph.JSRepr)
shouldExtractESMStmtsForWrap := repr.Meta.Wrap != graph.WrapNone

var moduleExportsOrNil js_ast.Expr
if c.options.OutputFormat == config.FormatCommonJS {
moduleExportsOrNil = js_ast.Expr{Data: &js_ast.EDot{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.unboundModuleRef}},
Name: "exports",
}}
} else {
moduleExportsOrNil = js_ast.Expr{Data: js_ast.ENullShared}
}

for _, stmt := range partStmts {
switch s := stmt.Data.(type) {
case *js_ast.SImport:
Expand Down Expand Up @@ -3547,14 +3583,15 @@ func (c *linkerContext) convertStmtsForChunk(sourceIndex uint32, stmtList *stmtL
ImportRecordIndex: s.ImportRecordIndex,
}

// Prefix this module with "__reExport(exports, ns)"
// Prefix this module with "__reExport(exports, module.exports, ns)"
exportStarRef := c.graph.Files[runtime.SourceIndex].InputFile.Repr.(*graph.JSRepr).AST.ModuleScope.Members["__reExport"].Ref
stmtList.insideWrapperPrefix = append(stmtList.insideWrapperPrefix, js_ast.Stmt{
Loc: stmt.Loc,
Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.ECall{
Target: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: exportStarRef}},
Args: []js_ast.Expr{
{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}},
moduleExportsOrNil,
{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: s.NamespaceRef}},
},
}}},
Expand All @@ -3579,12 +3616,12 @@ func (c *linkerContext) convertStmtsForChunk(sourceIndex uint32, stmtList *stmtL
var target js_ast.E
if record.SourceIndex.IsValid() {
if otherRepr := c.graph.Files[record.SourceIndex.GetIndex()].InputFile.Repr.(*graph.JSRepr); otherRepr.AST.ExportsKind == js_ast.ExportsESMWithDynamicFallback {
// Prefix this module with "__reExport(exports, otherExports)"
// Prefix this module with "__reExport(exports, module.exports, otherExports)"
target = &js_ast.EIdentifier{Ref: otherRepr.AST.ExportsRef}
}
}
if target == nil {
// Prefix this module with "__reExport(exports, require(path))"
// Prefix this module with "__reExport(exports, module.exports, require(path))"
target = &js_ast.ERequireString{
ImportRecordIndex: s.ImportRecordIndex,
}
Expand All @@ -3596,6 +3633,7 @@ func (c *linkerContext) convertStmtsForChunk(sourceIndex uint32, stmtList *stmtL
Target: js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: exportStarRef}},
Args: []js_ast.Expr{
{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}},
moduleExportsOrNil,
{Loc: record.Range.Loc, Data: target},
},
}}},
Expand Down Expand Up @@ -4097,25 +4135,6 @@ func (c *linkerContext) generateEntryPointTailJS(
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: repr.AST.WrapperRef}},
}}}})
}

// Decorate "module.exports" with the "__esModule" flag to indicate that
// we used to be an ES module. This is done by wrapping the exports object
// instead of by mutating the exports object because other modules in the
// bundle (including the entry point module) may do "import * as" to get
// access to the exports object and should NOT see the "__esModule" flag.
if repr.Meta.ForceIncludeExportsForEntryPoint {
// "module.exports = __toCommonJS(exports);"
stmts = append(stmts, js_ast.AssignStmt(
js_ast.Expr{Data: &js_ast.EDot{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: c.unboundModuleRef}},
Name: "exports",
}},
js_ast.Expr{Data: &js_ast.ECall{
Target: js_ast.Expr{Data: &js_ast.EIdentifier{Ref: toCommonJSRef}},
Args: []js_ast.Expr{{Data: &js_ast.EIdentifier{Ref: repr.AST.ExportsRef}}},
}},
))
}
}

// If we are generating CommonJS for node, encode the known export names in
Expand Down
8 changes: 4 additions & 4 deletions internal/bundler/snapshots/snapshots_default.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -857,8 +857,8 @@ TestExportWildcardFSNodeCommonJS
---------- /out.js ----------
// entry.js
var entry_exports = {};
__reExport(entry_exports, require("fs"));
module.exports = __toCommonJS(entry_exports);
__reExport(entry_exports, module.exports, require("fs"));

================================================================================
TestExportWildcardFSNodeES6
Expand Down Expand Up @@ -938,7 +938,7 @@ var e_exports = {};
import * as x_star from "x";
var init_e = __esm({
"e.js"() {
__reExport(e_exports, x_star);
__reExport(e_exports, null, x_star);
}
});

Expand Down Expand Up @@ -2364,11 +2364,11 @@ __export(entry_exports, {
bar: () => import_bar.default,
foo: () => import_foo.default
});
module.exports = __toCommonJS(entry_exports);
var import_foo = __toESM(require("foo"));

// bar.js
var import_bar = __toESM(require("bar"));
module.exports = __toCommonJS(entry_exports);

================================================================================
TestReExportDefaultExternalES6
Expand Down Expand Up @@ -2410,9 +2410,9 @@ __export(entry_exports, {
bar: () => import_bar.default,
foo: () => import_foo.default
});
module.exports = __toCommonJS(entry_exports);
var import_foo = __toESM(require("./foo"));
var import_bar = __toESM(require("./bar"));
module.exports = __toCommonJS(entry_exports);

================================================================================
TestReExportDefaultNoBundleES6
Expand Down
30 changes: 15 additions & 15 deletions internal/bundler/snapshots/snapshots_importstar.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,8 @@ var entry_exports = {};
__export(entry_exports, {
ns: () => ns
});
var ns = __toESM(require_foo());
module.exports = __toCommonJS(entry_exports);
var ns = __toESM(require_foo());

================================================================================
TestExportOtherCommonJS
Expand All @@ -30,8 +30,8 @@ var entry_exports = {};
__export(entry_exports, {
bar: () => import_foo.bar
});
var import_foo = __toESM(require_foo());
module.exports = __toCommonJS(entry_exports);
var import_foo = __toESM(require_foo());

================================================================================
TestExportOtherNestedCommonJS
Expand All @@ -48,10 +48,10 @@ var entry_exports = {};
__export(entry_exports, {
y: () => import_foo.x
});
module.exports = __toCommonJS(entry_exports);

// bar.js
var import_foo = __toESM(require_foo());
module.exports = __toCommonJS(entry_exports);

================================================================================
TestExportSelfAndImportSelfCommonJS
Expand All @@ -61,9 +61,9 @@ var entry_exports = {};
__export(entry_exports, {
foo: () => foo
});
module.exports = __toCommonJS(entry_exports);
var foo = 123;
console.log(entry_exports);
module.exports = __toCommonJS(entry_exports);

================================================================================
TestExportSelfAndRequireSelfCommonJS
Expand All @@ -73,6 +73,7 @@ var entry_exports = {};
__export(entry_exports, {
foo: () => foo
});
module.exports = __toCommonJS(entry_exports);
var foo;
var init_entry = __esm({
"entry.js"() {
Expand All @@ -81,7 +82,6 @@ var init_entry = __esm({
}
});
init_entry();
module.exports = __toCommonJS(entry_exports);

================================================================================
TestExportSelfAsNamespaceCommonJS
Expand All @@ -92,8 +92,8 @@ __export(entry_exports, {
foo: () => foo,
ns: () => entry_exports
});
var foo = 123;
module.exports = __toCommonJS(entry_exports);
var foo = 123;

================================================================================
TestExportSelfAsNamespaceES6
Expand All @@ -118,8 +118,8 @@ var entry_exports = {};
__export(entry_exports, {
foo: () => foo
});
var foo = 123;
module.exports = __toCommonJS(entry_exports);
var foo = 123;

================================================================================
TestExportSelfCommonJSMinified
Expand Down Expand Up @@ -169,10 +169,10 @@ var entry_exports = {};
__export(entry_exports, {
foo: () => foo
});
module.exports = __toCommonJS(entry_exports);

// foo.js
var foo = "foo";
module.exports = __toCommonJS(entry_exports);

================================================================================
TestImportDefaultNamespaceComboIssue446
Expand Down Expand Up @@ -275,8 +275,8 @@ var entry_exports = {};
__export(entry_exports, {
ns: () => ns
});
var ns = __toESM(require_foo());
module.exports = __toCommonJS(entry_exports);
var ns = __toESM(require_foo());

================================================================================
TestImportExportSelfAsNamespaceES6
Expand Down Expand Up @@ -869,8 +869,8 @@ var entry_exports = {};
__export(entry_exports, {
out: () => out
});
var out = __toESM(require("foo"));
module.exports = __toCommonJS(entry_exports);
var out = __toESM(require("foo"));

================================================================================
TestReExportStarAsES6NoBundle
Expand All @@ -888,8 +888,8 @@ var entry_exports = {};
__export(entry_exports, {
out: () => out
});
var out = __toESM(require("foo"));
module.exports = __toCommonJS(entry_exports);
var out = __toESM(require("foo"));

================================================================================
TestReExportStarAsExternalES6
Expand Down Expand Up @@ -929,8 +929,8 @@ var mod = (() => {
TestReExportStarCommonJSNoBundle
---------- /out.js ----------
var entry_exports = {};
__reExport(entry_exports, require("foo"));
module.exports = __toCommonJS(entry_exports);
__reExport(entry_exports, module.exports, require("foo"));

================================================================================
TestReExportStarES6NoBundle
Expand All @@ -942,8 +942,8 @@ TestReExportStarExternalCommonJS
---------- /out.js ----------
// entry.js
var entry_exports = {};
__reExport(entry_exports, require("foo"));
module.exports = __toCommonJS(entry_exports);
__reExport(entry_exports, module.exports, require("foo"));

================================================================================
TestReExportStarExternalES6
Expand All @@ -957,7 +957,7 @@ TestReExportStarExternalIIFE
var mod = (() => {
// entry.js
var entry_exports = {};
__reExport(entry_exports, __require("foo"));
__reExport(entry_exports, null, __require("foo"));
return __toCommonJS(entry_exports);
})();

Expand All @@ -966,7 +966,7 @@ TestReExportStarIIFENoBundle
---------- /out.js ----------
var mod = (() => {
var entry_exports = {};
__reExport(entry_exports, require("foo"));
__reExport(entry_exports, null, require("foo"));
return __toCommonJS(entry_exports);
})();

Expand Down
10 changes: 5 additions & 5 deletions internal/bundler/snapshots/snapshots_loader.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -903,9 +903,10 @@ export default {
TestToESMWrapperOmission
---------- /out/entry.js ----------
var entry_exports = {};
module.exports = __toCommonJS(entry_exports);
var import_a_nowrap = require("a_nowrap");
var import_b_nowrap = require("b_nowrap");
__reExport(entry_exports, require("c_nowrap"));
__reExport(entry_exports, module.exports, require("c_nowrap"));
var d = __toESM(require("d_WRAP"));
var import_e_WRAP = __toESM(require("e_WRAP"));
var import_f_WRAP = __toESM(require("f_WRAP"));
Expand All @@ -922,7 +923,6 @@ x = h;
i.x();
j.x``;
x = Promise.resolve().then(() => __toESM(require("k_WRAP")));
module.exports = __toCommonJS(entry_exports);

================================================================================
TestWarnCommonJSExportsInESMBundle
Expand All @@ -932,10 +932,10 @@ var cjs_in_esm_exports = {};
__export(cjs_in_esm_exports, {
foo: () => foo
});
module.exports = __toCommonJS(cjs_in_esm_exports);
var foo = 1;
exports.foo = 2;
module.exports = 3;
module.exports = __toCommonJS(cjs_in_esm_exports);

---------- /out/import-in-cjs.js ----------
// import-in-cjs.js
Expand All @@ -954,19 +954,19 @@ var cjs_in_esm_exports = {};
__export(cjs_in_esm_exports, {
foo: () => foo
});
module.exports = __toCommonJS(cjs_in_esm_exports);
let foo = 1;
exports.foo = 2;
module.exports = 3;
module.exports = __toCommonJS(cjs_in_esm_exports);

---------- /out/cjs-in-esm2.js ----------
var cjs_in_esm2_exports = {};
__export(cjs_in_esm2_exports, {
foo: () => foo
});
module.exports = __toCommonJS(cjs_in_esm2_exports);
let foo = 1;
module.exports.bar = 3;
module.exports = __toCommonJS(cjs_in_esm2_exports);

---------- /out/import-in-cjs.js ----------
var import_bar = require("bar");
Expand Down
8 changes: 5 additions & 3 deletions internal/runtime/runtime.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -185,7 +185,9 @@ func code(isES6 bool) string {
for (var name in all)
__defProp(target, name, { get: all[name], enumerable: true })
}
export var __reExport = (target, module, copyDefault, desc) => {
export var __reExport = (target, secondTarget, module, copyDefault, desc) => {
if (secondTarget && secondTarget !== target)
__reExport(secondTarget, null, module, copyDefault, desc)
if (module && typeof module === 'object' || typeof module === 'function')
`

Expand Down Expand Up @@ -225,14 +227,14 @@ func code(isES6 bool) string {
!isNodeMode && module && module.__esModule
? { get: () => module.default, enumerable: true }
: { value: module, enumerable: true })
), module)
), null, module)
}
// Converts the module from ESM to CommonJS
export var __toCommonJS = /* @__PURE__ */ (cache => {
return (module, temp) => {
return (cache && cache.get(module)) || (
temp = __reExport(__markAsModule({}), module, /* copyDefault */ 1),
temp = __reExport(__markAsModule({}), null, module, /* copyDefault */ 1),
cache && cache.set(module, temp),
temp)
}
Expand Down
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