lock-and-yield

Lock and Yield

For asynchronous functions. Per given key, only executes one underlying function at a time (such as API call).

API

var lock = require('lock-and-yield')

var fn = lock(function* (url) {
  return yield request(url)
}, function (url) {
  return url
})

// only 1 HTTP request will be called:
co(function* () {
  yield [
    fn(url),
    fn(url),
  ]
})()

fn = lock(fn, hashfn)

fn is a GeneratorFunction. hashfn is a hashing function based on the arguments passed to fn. By default, it is (arg) -> String(arg).

fn = lock(fn, number)

hashfn will be () -> String(arguments[number]).

License

The MIT License (MIT)

Copyright (c) 2014 Jonathan Ong [e-mail]

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.