This is a small library to limit the amount of promises run per unit of time. It is useful for scenarios such as Rest APIs consumption, where we are normally rate-limited to a certain amount of requests per time.
It doesn't have any dependencies. If you are running this on Node.js, you will need to pass whatever Promise library you are using in the constructor.
Then, you add functions to the PromiseThrottle that, once called, return a Promise.
The library can be used either server-side or in the browser.
var PromiseThrottle = require('promise-throttle');
/**
* A function that once called returns a promise
* @return Promise
*/
var myFunction = function(i) {
return new Promise(function(resolve, reject) {
// here we simulate that the promise runs some code
// asynchronously
setTimeout(function() {
console.log(i + ": " + Math.random());
resolve(i);
}, 10);
});
};
var promiseThrottle = new PromiseThrottle({
requestsPerSecond: 1, // up to 1 request per second
promiseImplementation: Promise // the Promise library you are using
});
var amountOfPromises = 10;
while (amountOfPromises-- > 0) {
promiseThrottle.add(myFunction.bind(this, amountOfPromises))
.then(function(i) {
console.log("Promise " + i + " done");
});
}
// example using Promise.all
var one = promiseThrottle.add(myFunction.bind(this, 1));
var two = promiseThrottle.add(myFunction.bind(this, 2));
var three = promiseThrottle.add(myFunction.bind(this, 3));
Promise.all([one, two, three])
.then(function(r) {
console.log("Promises " + r.join(", ") + " done");
});For node.js, install the module with: npm i promise-throttle
If you are using it in a browser, you can use bower: bower install promise-throttle
Install the dependencies using make install.
Run make to lint, test and generate the dist file.
See how some projects are using it:
MIT