co-future

Wrap a generator function in a future for fine-grained resolution control.

Installation

Node.js

co-future is available through npm:

npm install co-future

Example

var co = require('co');
var future = require('co-future');

function *blk() {
  yield wait(100); // async stuff
  return { hello: 'universe' };
}

co(function *main() {
  var fut = future(blk);          // start calc

  yield wait(50);                 // do other things
  yield fut.wait();               // wait for resolution

  if (fut.err) {                  // check for error
    var msg = fut.err.message;
    console.error('error:', msg); 
  }

  console.log(fut.unwrap());      // unwrap val or throw error
})();

Usage

Future implementation for generator functions. Wraps and invokes generator using co on construction. Will not throw error of resolved future until .unwrap() so can be used as generator try/catch replacement.

• @param {Generator} closure
• @param {Array} argv
• @param {Mixed} context for closure

var future = require('co-future');

function*() {
  var res = yield future(do.something()).wait();
  return res.unwrap();
}

.err

Get error or false of resolved future. Unlike .unwrap(), will not throw.

• @return {Mixed} error or false

if (fut.err) console.error(fut.err.message);

.res

Get result or undefined of resolved future.

• @return {Boolean} resolved

if (!fut.err) console.log(fut.res);

.wait()

Wait for future to resolve. On resolution will yield the future for further chaining. Use .unwrap() to get actual value.

// wait immediately on new future
var fut = yield future(do.something(req)).wait();

// wait for existing future
yield fut.wait();

.unwrap()

Unwrap the value stored in the future after resolution. If the future is currently storing an error it will be thrown.

• @return {Mixed} success result

return res.unwrap();

License

(The MIT License)

Copyright (c) 2014 Jake Luer [email protected]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.