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feat: introduce API parity between JS and WASM implementation #27

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Merged
guybedford merged 1 commit into from
Nov 1, 2020
Merged

feat: introduce API parity between JS and WASM implementation #27

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4 changes: 3 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,9 @@ npm install cjs-module-lexer
For use in CommonJS:

```js
const parse = require('cjs-module-lexer');
const { parse, init } = require('cjs-module-lexer');

@SimenB SimenB Nov 1, 2020

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not sure if we should require it to be called or not. E.g. what happens if I use import('cjs-module-lexer')? Possibly confusing. Dunno 🙂

@SimenB SimenB Nov 1, 2020

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since we're changing the API regardless it might be worth it. happy to make the change if you want 👍

@guybedford guybedford Nov 1, 2020

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Strictly speaking, the way the exports are defined in https://github.com/guybedford/cjs-module-lexer/blob/master/package.json#L6, import() should always get the ES module form by definition of the resolution rules and even in bundlers (which RollupJS and Webpack support now!)


// `init` return a promise for parity with the ESM API, but you do not have to call it

const { exports, reexports } = parse(`
// named exports detection
Expand Down
15 changes: 10 additions & 5 deletions lexer.js
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Expand Up @@ -37,7 +37,7 @@ const ExportStar = 2;

const strictReserved = new Set(['implements', 'interface', 'let', 'package', 'private', 'protected', 'public', 'static', 'yield', 'enum']);

module.exports = function parseCJS (source, name = '@') {
function parseCJS (source, name = '@') {
resetState();
try {
parseSource(source);
Expand Down Expand Up @@ -899,7 +899,7 @@ function tryParseLiteralExports () {

// --- Extracted from AcornJS ---
//(https://github.com/acornjs/acorn/blob/master/acorn/src/identifier.js#L23
//
//
// MIT License

// Copyright (C) 2012-2018 by various contributors (see AUTHORS)
Expand Down Expand Up @@ -1034,7 +1034,7 @@ function throwIfImportStatement () {
case 46/*.*/:
throw new Error('Unexpected import.meta in CJS module.');
return;

default:
// no space after "import" -> not an import keyword
if (pos === startPos + 6)
Expand Down Expand Up @@ -1203,7 +1203,7 @@ function readPrecedingKeyword (pos, match) {
}

function readPrecedingKeyword1 (pos, ch) {
return source.charCodeAt(pos) === ch && (pos === 0 || isBrOrWsOrPunctuatorNotDot(source.charCodeAt(pos - 1)));
return source.charCodeAt(pos) === ch && (pos === 0 || isBrOrWsOrPunctuatorNotDot(source.charCodeAt(pos - 1)));
}

// Detects one of case, debugger, delete, do, else, in, instanceof, new,
Expand Down Expand Up @@ -1274,7 +1274,7 @@ function isExpressionKeyword (pos) {
// throw
return readPrecedingKeyword(pos - 2, 'thr');
default:
return false;
return false;
}
}
return false;
Expand Down Expand Up @@ -1320,3 +1320,8 @@ function isExpressionTerminator (curPos) {
}
return false;
}

const initPromise = Promise.resolve();

module.exports.init = () => initPromise;
module.exports.parse = parseCJS;
Comment on lines +1326 to +1327

@nicolo-ribaudo nicolo-ribaudo Nov 1, 2020

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Note that this could be done without breaking changes:

module.exports = (source, name) => parseCJS(source, name);
module.exports.init = () => initPromise;
module.exports.parse = parseCJS;

@SimenB SimenB Nov 1, 2020

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good point. @guybedford thoughts?

@guybedford guybedford Nov 1, 2020

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Let's keep it simple as a major change actually. Saves on type differences / leaving deprecation for subsequent work.