https://github.com/mvaldesdeleon/long-promise

Long stack traces for Promises (Node 8 only).
https://github.com/mvaldesdeleon/long-promise

async-hooks node promise stack stacktrace

Last synced: about 1 month ago
JSON representation

Long stack traces for Promises (Node 8 only).

• Host: GitHub
• URL: https://github.com/mvaldesdeleon/long-promise
• Owner: mvaldesdeleon
• License: other
• Created: 2017-06-01T19:23:51.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-06-02T08:53:41.000Z (over 7 years ago)
• Last Synced: 2024-11-07T07:18:33.193Z (about 2 months ago)
• Topics: async-hooks, node, promise, stack, stacktrace
• Language: JavaScript
• Size: 13.7 KB
• Stars: 12
• Watchers: 3
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
# long-promise

Long stack traces with Promises, using the brand-new `async_hooks` API provided by Node 8.0.0.

```JS

const lp = require('long-promise');

lp.enable();

// Simulate some stuff

const stuff = x => 2 + x;

// Simulate a delay.

const delay = ms => x => {

    // This function is `buggy` and will throw if the delay is 100ms.

    if (ms === 100) throw new Error('boom');

    return new Promise(res => {

        setTimeout(() => {

            res(x);

        }, ms);

    });

};

const nestedProblems = x => () => {

    // After the third call, go to an eventual `delay(100)` that throws

    if (x === 3) return Promise.resolve(1).then(delay(100));

    // Promise chain with recursion

    return Promise.resolve(1)

        .then(delay(10))

        .then(stuff)

        .then(nestedProblems(x + 1));

};

// Main program

function run() {

    const p = Promise.resolve(2);

    // Do some things. Something along this promise chain will throw.

    p.then(stuff)

        .then(delay(10))

        .then(stuff)

        .then(delay(10))

        .then(stuff)

        .then(nestedProblems(1))

        .then(stuff)

        .then(stuff)

        .catch(err => {

            console.log(lp.getLongStack(err));

            // Profit

        });

}

run();

```

This produces the following stack trace:

```

Error: boom

    at x (/Users/mvaldes/Sandbox/long-promise/example.js:12:27)

    at 

    at Promise.then ()

    at /Users/mvaldes/Sandbox/long-promise/example.js:23:44

    at 

    at Promise.then ()

    at /Users/mvaldes/Sandbox/long-promise/example.js:29:10

    at 

    at Promise.then ()

    at /Users/mvaldes/Sandbox/long-promise/example.js:29:10

    at 

    at Promise.then ()

    at run (/Users/mvaldes/Sandbox/long-promise/example.js:42:10)

    at Object. (/Users/mvaldes/Sandbox/long-promise/example.js:51:1)

    at Module._compile (module.js:569:30)

    at Object.Module._extensions..js (module.js:580:10)

```

Without `long-promise` enabled, the original stack trace is the following:

```

Error: boom

    at x (/Users/mvaldes/Sandbox/long-promise/example.js:12:27)

    at 

```

This is very early work, any contributions are welcome.

# install

with [npm](https://npmjs.org) do:

```

npm install long-promise

```

# license

MIT