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https://github.com/dustinlarimer/multitask
Gulp-style control flow for keeping asynchronous tasks in line
https://github.com/dustinlarimer/multitask
Last synced: 13 days ago
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Gulp-style control flow for keeping asynchronous tasks in line
- Host: GitHub
- URL: https://github.com/dustinlarimer/multitask
- Owner: dustinlarimer
- Created: 2015-01-07T22:51:12.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2015-04-24T21:27:35.000Z (over 9 years ago)
- Last Synced: 2024-09-17T00:17:01.060Z (2 months ago)
- Language: JavaScript
- Homepage:
- Size: 184 KB
- Stars: 6
- Watchers: 1
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# multitask
## How it works
### Create tasks
`.set` defines a task and its optional dependencies. Tasks and task dependencies are wrapped with [Bluebird](https://github.com/petkaantonov/bluebird) promises. Each task will be called with a last argument (explained below) containing a "done" function that completes the task and optionally returns a value.
```javascript
multitask
.set('first task', function(done){
// do some asynchronous work and call done()
done({ response: "tada!" });
})
.set('next task', ['list', 'of', 'dependent', 'tasks'], function(res, done){
// notice this task depends on others ^
// insert an argument to get an array of values returned by them ^ ...
done({ task_count: res.length });
})
.set('task three', ['first task', 'next task'], function(done){
// ... or omit that extra argument if the results of dependent tasks are not needed
// the -last- argument will always be a `done` function
});
```
### Run tasks and handle responses
`.run` returns a [Bluebird](https://github.com/petkaantonov/bluebird) promise, which exposes a `then` method (for handling results) and a `catch` method (for catching errors).
```javascript
multitask
.run(['list', 'of', 'tasks'])
.then(function(res){
/* res == array containing results of all tasks */
})
.catch(function(err){
/* err == any errors thrown by tasks */
});
```
### Reset before re-running
If you're running tasks with a cron or interval, `.reset` will clear out previous results before re-running. This can be useful when hitting an API for time-sensitive data.
```javascript
multitask
.reset()
.run(['first', 'next']);
```
## Example implementation
```javascript
var tasks = require('./');
tasks.set('stage 1', function(done){
setTimeout(function(){
done(1);
}, 1000);
});
tasks.set('stage 2', ['stage 1'], function(result, done){
// receive prior result by providing argument ^
setTimeout(function(){
done(result * 2);
}, 2000);
});
mtask.set('report', ['stage 2', 'stage 1'], function(result, done){
done( result[0] + result[1] );
});
function init(){
mtask
.reset()
.run(['report', undefined, 'also undefined', 'stage 1', 'stage 2'])
.then(function(result){
console.log('done', result);
})
.catch(function(err){
console.log('err', err);
});
}
init();
setInterval(init, 5000);
```
Output
1. 'stage 1' task begins (1000ms pause)
2. 'stage 2' task begins (2000ms pause)
3. 'report' task begins
4. runner exits with arguments `{ '0': [ 2, 1 ], '1': [Function] }`
5. runner logs 'done' with arguments `{ '0': [ 3, undefined, 'also undefined', 1, 2 ] }`