importHelpers not respected when exporting defaults

[jordanrastrick]

🔎 Search Terms

"importHelpers"

"default exports"

"tslib"

🕗 Version & Regression Information

• This is a crash
• This changed between versions ______ and _______
• This changed in commit or PR _______
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about _________
• I was unable to test this on prior versions because _______

⏯ Playground Link

Can't create playground as multiple files are required to demonstrate

💻 Code

src/exporter.ts:

export default function foo(): boolean {
    return true
}

src/index.ts:

export { default as foo } from './exporter'

🙁 Actual behavior

With importHelpers set to true and noEmitHelpers set to false I expect src/index.ts to be compiled to something like:

"use strict";
const tslib_1 = require("tslib");
Object.defineProperty(exports, "__esModule", { value: true });
exports.foo = void 0;
var exporter_1 = require("./exporter");
Object.defineProperty(exports, "foo", { enumerable: true, get: function () { return tslib_1.__importDefault(exporter_1).default; } });

🙂 Expected behavior

src/index.ts is actually compiled to:

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.foo = void 0;
var exporter_1 = require("./exporter");
Object.defineProperty(exports, "foo", { enumerable: true, get: function () { return __importDefault(exporter_1).default; } });

i.e. it appears for an export { default as ... } statement, the importHelpers property is being ignored.

Additional information about the issue

No response

[jakebailey]

This does show in the playground: Playground Link

But, it's also fixed in 5.5.

[jakebailey]

Fix was in #57220, so this is a dupe of #40328.

[typescript-bot]

This issue has been marked as "Duplicate" and has seen no recent activity. It has been automatically closed for house-keeping purposes.