GeezerVison

0.5.0

- Breaking Change: No longer emit Object.defineProperty exports (https://github.com/guybedford/cjs-module-lexer/pull/24)

- Doc: Update link to WASI SDK (https://github.com/guybedford/cjs-module-lexer/pull/19)

0.4.3

- Support for Babel 7.12 reexports (https://github.com/guybedford/cjs-module-lexer/pull/16)

- Support module.exports = { ...require('x') } reexports (https://github.com/guybedford/cjs-module-lexer/pull/18)

* The returned export names are the matched `IDENTIFIER` and `IDENTIFIER_STRING` slots for all `EXPORTS_MEMBER`, `EXPORTS_DEFINE` and `EXPORTS_LITERAL` matches.

* The reexport specifiers are taken to be the `STRING_LITERAL` slots of all `MODULE_EXPORTS_ASSIGN` as well as all _top-level_ `EXPORT_STAR` `REQUIRE` matches and `EXPORTS_ASSIGN` matches whose `IDENTIFIER` also matches the first `IDENTIFIER` in `EXPORT_STAR_LIB`.

* The returned export names are taken to be the combination of:

1. `IDENTIFIER` and `IDENTIFIER_STRING` slots for all `EXPORTS_MEMBER` and `EXPORTS_LITERAL` matches.

2. `__esModule` if there is an `ES_MODULE_DEFINE` match.

* The reexport specifiers are taken to be the the combination of:

1. The `REQUIRE` matches of the last matched of either `MODULE_EXPORTS_ASSIGN` or `EXPORTS_LITERAL`.

2. All _top-level_ `EXPORT_STAR` `REQUIRE` matches and `EXPORTS_ASSIGN` matches whose `IDENTIFIER` also matches the first `IDENTIFIER` in `EXPORT_STAR_LIB`.

The basic matching rules for named exports are `exports.name`, `exports['name']` or `Object.defineProperty(exports, 'name', ...)`. This matching is done without scope analysis and regardless of the expression position:

(function (exports) {

exports.a = 'a';

exports['b'] = 'b';

Object.defineProperty(exports, 'c', { value: 'c' });

})(exports);

exports.a = 'a';

exports['b'] = 'b';

if (false)

Object.defineProperty(exports, 'c', { value: 'c' });

exports.c = 'c';

})(NOT_EXPORTS, NOT_OBJECT);

It will in turn underclassify in cases where the identifiers are renamed:

(function (e, defineProperty) {

(function (e) {

e.a = 'a';

e['b'] = 'b';

defineProperty(e, 'c', { value: 'c' });

})(exports, defineProperty);

})(exports);

In addition, `__esModule` is detected as an export when set by `Object.defineProperty`:

Object.defineProperty(exports, 'a', { value: 'a' });

Object.defineProperty(exports, '__esModule', { value: true });

No other named exports are detected for `defineProperty` calls in order not to trigger getters or non-enumerable properties unnecessarily.

A best-effort is made to detect `module.exports` object assignments, but because this is not a full parser, arbitrary expressions are not handled in the

module.exports = {

a,

b: 'c',

c: c

'b': b,

c: c,

...d

};

Object properties that are not identifiers or string expressions will bail out of the object detection:

Object properties that are not identifiers or string expressions will bail out of the object detection, while spreads are ignored:

module.exports = {

a,

...d,

b: require('c'),

c: "not detected since require('c') above bails the object detection"

}

Any `module.exports = require('mod')` assignment is detected as a reexport:

Any `module.exports = require('mod')` assignment is detected as a reexport, but only the last one is returned:

module.exports = require('a');

(module => module.exports = require('b'))(NOT_MODULE);

if (false) module.exports = require('c');

As a result, the total list of exports would be inferred as the union of all of these reexported modules, which can lead to possible over-classification.

This is to avoid over-classification in Webpack bundles with externals which include `module.exports = require('external')` in their source for every external dependency.

In exports object assignment, any spread of `require()` are detected as multiple separate reexports:

module.exports = require('ignored');

module.exports = {

...require('a'),

...require('b')

};

JS Build:

Wasm Build:

To build download the WASI SDK from https://github.com/CraneStation/wasi-sdk/releases.

To build download the WASI SDK from https://github.com/WebAssembly/wasi-sdk/releases.

The Makefile assumes the existence of "wasi-sdk-10.0", "binaryen" and "wabt" (both optional) as sibling folders to this project.

The Makefile assumes the existence of "wasi-sdk-11.0" and "wabt" (optional) as sibling folders to this project.

The build through the Makefile is then run via `make lib/lexer.wasm`, which can also be triggered via `npm run build-wasm` to create `dist/lexer.js`.

const exportPos = ++pos;

if (identifier() && source.charCodeAt(pos) === ch) {

// revert for "("

addExport(source.slice(exportPos, pos));

const expt = source.slice(exportPos, pos);

if (expt === '__esModule')

addExport(expt);

}

}

}

{

"name": "cjs-module-lexer",

"version": "0.4.3",

"version": "0.5.0",

"description": "Lexes CommonJS modules, returning their named exports metadata",

"main": "lexer.js",

"exports": {

[`transformSource` hook]: #esm_transformsource_source_context_defaulttransformsource

[`string`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String

[`util.TextDecoder`]: util.md#util_class_util_textdecoder

[cjs-module-lexer]: https://github.com/guybedford/cjs-module-lexer/tree/0.4.3

[cjs-module-lexer]: https://github.com/guybedford/cjs-module-lexer/tree/0.5.0

[special scheme]: https://url.spec.whatwg.org/#special-scheme

[the official standard format]: https://tc39.github.io/ecma262/#sec-modules

[transpiler loader example]: #esm_transpiler_loader

import { strictEqual, deepEqual } from 'assert';

import m, { π, z } from './exports-cases.js';

import m, { π } from './exports-cases.js';

import * as ns from './exports-cases.js';

deepEqual(Object.keys(ns), ['default', 'isObject', 'z', 'π']);

deepEqual(Object.keys(ns), ['default', 'isObject', 'π']);

strictEqual(π, 'yes');

strictEqual(z, 'yes');

strictEqual(typeof m.isObject, 'undefined');

strictEqual(m.π, 'yes');

strictEqual(m.z, 'yes');

strictEqual(m2.default, 'the default');

strictEqual(ns2.__esModule, true);

strictEqual(ns2.name, 'name');

deepEqual(Object.keys(ns2), ['__esModule', 'case2', 'default', 'name', 'pi']);

deepEqual(Object.keys(ns2), ['__esModule', 'case2', 'default', 'name']);

import m3, { __esModule as __esModule3, name as name3 } from './exports-cases3.js';

import * as ns3 from './exports-cases3.js';