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https://github.com/chengcyber/cjs-exports-parser
Parse CommonJS module, returns exports metadata
https://github.com/chengcyber/cjs-exports-parser
Last synced: 27 days ago
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Parse CommonJS module, returns exports metadata
- Host: GitHub
- URL: https://github.com/chengcyber/cjs-exports-parser
- Owner: chengcyber
- License: mit
- Created: 2020-12-02T05:38:51.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2020-12-07T06:30:13.000Z (almost 4 years ago)
- Last Synced: 2024-05-01T17:12:19.806Z (6 months ago)
- Language: TypeScript
- Size: 16.6 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# cjs-exports-parser
Parse cjs exports
# Usage
```
npm install cjs-exports-parser
```
```js
import { parseCode } from 'cjs-exports-parser';
const { exports, reexports } = parseCode(`
// named exports detection
module.exports.a = 'a';
(function () {
exports.b = 'b';
})();
Object.defineProperty(exports, 'c', { value: 'c' });
/* exports.d = 'not detected'; */
// reexports detection
if (maybe) module.exports = require('./dep1.js');
if (another) module.exports = require('./dep2.js');
// literal exports assignments
module.exports = { a, b: c, d, 'e': f }
// __esModule detection
Object.defineProperty(module.exports, '__esModule', { value: true })
`);
```
or
```js
import { parseFile } from 'cjs-exports-parser';
const { exports } = await parseFile('/absolute/path/to/your/file.js');
```
`parseFile` does not return `reexports`, because it automaticlly invokes recurrsively to collect `exports`.
# Cases
## Named Exports Parsing
```js
// DETECTS EXPORTS: a, b
(function (exports) {
exports.a = 'a';
exports['b'] = 'b';
})(exports);
```
❗️Could not opt-out property in falsy branch:
```js
exports.a = 'a';
exports['b'] = 'b';
if (false) exports.c = 'c';
```
❗️Could not opt-out `exports` as param name explicitly:
```js
// DETECTS EXPORTS: a, b, c
(function (exports, Object) {
exports.a = 'a';
exports['b'] = 'b';
if (false) exports.c = 'c';
})(NOT_EXPORTS, NOT_OBJECT);
```
Could detects exports as function parameter and use another formal variable name:
```js
// DETECTS: a, b
(function (e) {
e.a = 'a';
e['b'] = 'b';
})(exports);
```
```js
// DETECTS EXPORTS: NO EXPORTS
(function (exports, Object) {
exports.a = 'a';
exports['b'] = 'b';
if (false) exports.c = 'c';
})(NOT_EXPORTS, NOT_OBJECT);
```
## Getter Exports Parsing
`Object.defineProperty` are suppored, in this following cases the property will be taken into exports:
1. if `enumerable` exists, it must be `true` in descriptor
2. contains `value` or `getter`;
a. if `value` exists in descriptor
b. if `getter` exists, function must return `Identifier` or `MemberExpression` or `StringLiteral`
3. no other properties exists in descriptor
```js
// DETECTS: a, b, c, d, e, __esModule
Object.defineProperty(exports, 'a', {
enumerable: true,
get: function () {
return q.p;
},
});
Object.defineProperty(exports, 'b', {
enumerable: true,
get: function () {
return q['p'];
},
});
Object.defineProperty(exports, 'c', {
enumerable: true,
get() {
return b;
},
});
Object.defineProperty(exports, 'd', { value: 'd' });
Object.defineProperty(exports, 'e', {
enumerable: true,
get() {
return 'str';
},
});
Object.defineProperty(exports, '__esModule', { value: true });
```
❗️To avoid matching getters that have side effects, any getter for an export name that does not support the forms above will opt-out of the getter matching:
```js
// DETECTS: NO EXPORTS
Object.defineProperty(exports, 'a', {
get() {
return 'nope';
},
});
if (false) {
Object.defineProperty(module.exports, 'a', {
get() {
return dynamic();
},
});
}
```
❗️Alternative object definition structures or getter function bodies are not detected:
```js
// DETECTS: NO EXPORTS
Object.defineProperty(exports, 'a', {
enumerable: false,
get() {
return p;
},
});
Object.defineProperty(exports, 'b', {
configurable: true,
get() {
return p;
},
});
Object.defineProperty(exports, 'c', {
get: () => p,
});
Object.defineProperty(exports, 'd', {
enumerable: true,
get: function () {
return dynamic();
},
});
```
❗️`Object.defineProperties` is also not supported.
## Exports Object Parsing
❗️spreads are ignored
```js
// DETECTS EXPORTS: a, b, c
module.exports = {
a,
b: b,
c: c,
...d,
};
```
```js
// DETECTS EXPORTS: a, b, c
module.exports = {
a,
...d,
b: require('c'),
c: 'c',
};
```
## module.exports reexport assignment
Any `module.exports = require('mod')` assignment is detected as a reexport, but only the last one is returned:
```js
// DETECTS REEXPORTS: c
module.exports = require('a');
((module) => (module.exports = require('b')))(NOT_MODULE);
if (false) module.exports = require('c');
```
```js
// DETECTS REEXPORTS: a, b
module.exports = require('ignored');
module.exports = {
...require('a'),
...require('b'),
};
```
## Transpiler reexports
`babel`, `TS` and other bundlers would like to inject reexport helper functions
`babel`:
```js
// DETECT REEXPORTS: 'external'
'use strict';
exports.__esModule = true;
var _external = require('external');
Object.keys(_external).forEach(function (key) {
if (key === 'default' || key === '__esModule') return;
exports[key] = _external[key];
});
```
`TS`:
```js
'use strict';
var __createBinding =
(this && this.__createBinding) ||
(Object.create
? function (o, m, k, k2) {
if (k2 === undefined) k2 = k;
Object.defineProperty(o, k2, {
enumerable: true,
get: function () {
return m[k];
},
});
}
: function (o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
});
var __exportStar =
(this && this.__exportStar) ||
function (m, exports) {
for (var p in m)
if (p !== 'default' && !exports.hasOwnProperty(p))
__createBinding(exports, m, p);
};
Object.defineProperty(exports, '__esModule', { value: true });
__exportStar(require('./foo'), exports);
```
# NOTE
Normally, the results are more accurate than `cjs-module-lexer` since `cjs-exports-parser` do further analysis via `babel`, but if you do care about performance pretty much, please give `cjs-module-lexer` a try.
# LICENSE
MIT