javascript - Determining successfailure with node.js function async.retry - Stack Overflow

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I'm studying the node.js module async, but I have some problems with the function async.retry.

According to its github docs, the function will continue trying the task until it succeeds or chances are used up. But how can my task tell success or failure?

I tried the code below:

var async = require('async');

var opts = {
    count : -3
};

async.retry(5, function (cb, results) {
    ++this.count;
    console.log(this.count, results);
    if (this.count > 0) cb(null, this.count);
    else cb();
}.bind(opts), function (err, results) {
   console.log(err, results);
});

I expect it to run until count === 1, but it always prints this:

-2 undefined
undefined undefined

So how can I use the function correctly?

I'm studying the node.js module async, but I have some problems with the function async.retry.

According to its github docs, the function will continue trying the task until it succeeds or chances are used up. But how can my task tell success or failure?

I tried the code below:

var async = require('async');

var opts = {
    count : -3
};

async.retry(5, function (cb, results) {
    ++this.count;
    console.log(this.count, results);
    if (this.count > 0) cb(null, this.count);
    else cb();
}.bind(opts), function (err, results) {
   console.log(err, results);
});

I expect it to run until count === 1, but it always prints this:

-2 undefined
undefined undefined

So how can I use the function correctly?

• javascript
• node.js
• asynchronous
• node-async

Share Follow edited Mar 11, 2015 at 3:28 Nathan Tuggy 2,2442727 gold badges3232 silver badges3838 bronze badges asked Mar 11, 2015 at 2:39 Yao ZhaoYao Zhao 4,61344 gold badges2424 silver badges3333 bronze badges 1

• Thank you for showing the use of bind in the async task. I was just trying to figure out how to pass arguments. – M. Ali Commented Dec 16, 2015 at 12:23

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1 Answer 1

Sorted by: Reset to default 5

You want your else-branch to fail. For that, you need to pass something to the error parameter; currently you just pass undefined which signals success - and that's what you get back.

async.retry(5, function (cb, results) {
    ++this.count;
    console.log(this.count, results);
    if (this.count > 0) cb(null, this.count);
    else cb(new Error("count too low"));
}.bind(opts), function (err, results) {
   console.log(err, results);
});

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