nodejs / nodejs/cjs-module-lexer

Incompatibility with TypeScript (edge case)

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#76 3 comments 1 reaction 0 assignees View on GitHub

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edge case wontfix
Dominant language
JavaScript
Stars
262
Forks
31
Avg merge
9d 2h
Merged PRs (30d)
5

Description

I have a very simple TypeScript file:

export { default as bar } from './bar'

When transpiled with tsc (4.8) and esModuleInterop set to true the transpiled code will somehow look like this:

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.bar = void 0;
var bar_1 = require("./bar");
Object.defineProperty(exports, "bar", { enumerable: true, get: function () { return __importDefault(bar_1).default; } });

In this case, the lexer seems to be ignoring the bar export.

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the report using the TypeScript 4.8 output shown in the issue, then inspect how the lexer handles the require("./bar") call and its Object.defineProperty getter. Done means the named bar export is recognized for this transpiled pattern and the existing lexer behavior remains covered by a regression test.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, typescript
Domain
tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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