Improve output for re-exporting #16178
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liuxingbaoyu
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PR: Output optimization 🔬
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| Object.defineProperty(exports, name, { | ||
| enumerable: true, | ||
| get: function () { | ||
| return mod[name2 || name]; |
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This fails if name2 is the empty string:
export { "" as x } from "./mod"| if (key in exports && exports[key] === _foo[key]) return; | ||
| exports[key] = _foo[key]; | ||
| }); | ||
| __exportStar(require("foo")); |
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Does this still work the same with cjs-module-lexer?
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Yes, this is pattern detection for ts by cjs-module-lexer.
| var _dep = babelHelpers.interopRequireWildcard(require("dep"), true); | ||
| _export("default", _dep); | ||
| _export("name", _dep); | ||
| function _export(name, mod, name2) { |
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Could we move this to an helper?
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This function uses exports unless we pass it as a parameter.
| var _react = __exportStar(require("react")); | ||
| var _interop; | ||
| function __exportStar(mod) { | ||
| mod = _interop == 1 ? babelHelpers.interopRequireWildcard(mod) : mod; |
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Maybe we could move the interopRequireWildcard call to __exportStar(_interopRequireWildcard(require("react")), so that we don't need the _interop variable? If not, in cases where _interop always has the same value could we hard-code the correct branch of this ternary rather than leaving both?
| var _foo = require("foo"); | ||
| _export("bar", _foo); |
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How do these changes change the case of a cycle, where foo is importing bar from this file?
// output.js
export { bar } from "foo"
// foo
import { bar as b } from "output.js"
export const bar = 1;
console.log(bar);and
// output.js
export { bar } from "foo"
// foo
import { bar as b } from "output.js"
console.log(bar);
export const bar = 1;There was a problem hiding this comment.
I added these two tests and strangely there is no change in behavior. I'm surprised.🤔
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Thank you for your review! I'm marking it as draft for now to try and unify the behavior of |
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The new behavior is compatible with
cjs-module-lexerviaexports.x=void 0.When the user has enabled the
lazyoption or the oldbabel-plugin-transform-modules-commonjsis working with the newbabel-helper-module-transforms,implicitAssignmentExportswill beundefinedto follow the old behavior .Note that there is an observable behavioral difference here.
Named exports are now no longer
configurable: false.