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  • License ISC

A protex is a mutex that works with Promises

Package Exports

  • protex

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (protex) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

protex

protex is like a mutex but for Promises. That is, an instance executes one promise at a time and remains locked until the Promise is resolved.

Example:

var protex = require('protex')();

protex.isLocked(); // => false

// Submit a promise chain for execution.
// The protex instance will remain locked until the returned promise is fulfilled.
var promise = protex.exec(function() {
    return Promise.resolve()
        .then(task1)
        .then(function() {
            try {
                protex.exec(function() {
                    console.log("i won't run");
                });
            } catch (e) {
                protex.isLocked(); // => true
            }
        })
        .then(task2)
});

promise.then(function() {
    console.log("protex is now unlocked!");
});

Installation

npm

Get it:

npm install protex

Require it:

var protex = require('protex');

UMD etc.

Copy and paste build/protex.js or build/protex.min.js to your project.

API

var prx = protex()

Create a new protex.

prx.isLocked()

Returns true if currently locked, false otherwise.

prx.exec(thing)

Submit thing for execution. Throws an exception if currently locked.

thing can be either a function or a Promise, although functions are preferred - the reason being that Promises begin to execute the moment they are created, i.e. before prx.exec() is called, meaning that it's possible to circumvent the lock. Passing a function will correctly delay the instantation of the Promise until prx.exec() has been called and locking is complete.

If thing is a function and it doesn't return a Promise it is assumed that the function is synchronous and the protex is unlocked immediately after the call returns.

© 2014 Jason Frame [ @jaz303 / jason@onehackoranother.com ]

Released under the ISC license.