promise-retryer

provides an easy way to make promises retry based on exceptions or result validation

install

npm install promise-retryer

params

• delay (can be a number or function that returns a number, if its a function it gets called with an attempt argument)
• maxRetries (the maximum amount of retries)
• validate (validation promise)
• onError (callback function on errors, gets called with an error object and an attempt argument)
• onAttempt (callback function on attempts, gets called with an attempt argument)
• debug (enable verbose logging)
• name (this is useful for debugging purposes)

examples

heres a basic retry example

var PromiseRetryer = require('promise-retryer')(Promise);
 
PromiseRetryer.run({
    delay: 1000,
    maxRetries: 5,
    promise: function (attempt) {
        return makeAsyncRequest(); // returns a promise
    }
}).then(
    function (response) {
        console.log(response);
    },
    function (error) {
        console.log(error);
    }
);

and heres a little more advanced example with validation and custom delays

var PromiseRetryer = require('promise-retryer')(Promise);
 
PromiseRetryer.run({
    delay: function (attempt) {
        return attempt * 1000;
    },
    maxRetries: 5,
    promise: function (attempt) {
        return makeAsyncRequest(); // returns a promise
    },
    validate: function (response, attempt) {
        return new Promise(function (resolve, reject) {
            if (typeof response === 'object') {
                resolve(response);
            } else {
                reject(new Error('response was not an object'));
            }
        });
    }
}).then(
    function (response) {
        console.log(response);
    },
    function (error) {
        console.log(error);
    }
);