async-stack-trace-test.js

// Pretend this is the non-async library code we're calling in to.
function gap() {
    return new Promise(resolve => setTimeout(resolve, 1));
}
function f4() {
    return new Promise((resolve, reject) => {
        gap().then(() => reject(new Error('from f4')));
    });
}

// This is our own native async code.
async function f3() {
    await gap();
    try {
        await f4();
    } catch (err) {
        // Instead of relaying the original Error, create a new one.
        // Since we're part of a chain of native async functions, the
        // new Error should have a good stack trace.
        throw new Error('from f3');
    }
}
async function f2() {
    await gap();
    await f3();
}
async function f1() {
    await gap();
    await f2();
}
f1()
    .then(() => console.log('done'))
    .catch(err => { console.log(err.stack); });