asyncToGenerator function unrolls secondary parameter if it is an array

[finnboeger]

Calling an async function with the result of two async functions that both return an array leads to the second array being unrolled and each member of it being passed as a seperate parameter to the function.

With a and b being

async function a(): Promise<string[]> {
    return [1,2];
}

async function b(x: string[], y: string[]): Promise<void> {
    console.log(x, y);
    console.log(...x, ...y);
}

the following code is being transpiled incorrectly:

(
    async () => b(await a(), await a())
)().then();

into

_asyncToGenerator(function() {
    var _tmp;
    return __generator(this, function(_state) {
        switch(_state.label){
            case 0:
                return [
                    4,
                    a()
                ];
            case 1:
                _tmp = [
                    _state.sent()
                ];
                return [
                    4,
                    a()
                ];
            case 2:
                return [
                    2,
                    b.apply(void 0, _tmp.concat(_state.sent()))
                ];
        }
    });
})().then();

whereas the line b.apply(void 0, _tmp.concat(_state.sent())) should be instead b.apply(void 0, _tmp.push(_state.sent()))

The issue is reproduced here: https://github.com/finnboeger/swc-loader-async-bug

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.