├── .gitignore
├── History.md
├── Makefile
├── Readme.md
├── component.json
├── index.js
├── package.json
└── test
    └── index.js


/.gitignore:
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1 | node_modules/
2 | 


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/History.md:
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 1 | 
 2 | v1.1.0 / 2014-11-23
 3 | ===================
 4 | 
 5 |  * make jitter proportional to backoff duration
 6 | 
 7 | 1.0.1 / 2014-02-17
 8 | ==================
 9 | 
10 |  * go away decimal point
11 |  * history
12 | 
13 | 1.0.0 / 2014-02-17
14 | ==================
15 | 
16 |  * add jitter option
17 |  * Initial commit
18 | 


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/Makefile:
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1 | 
2 | test:
3 | 	@./node_modules/.bin/mocha \
4 | 		--require should \
5 | 		--reporter dot \
6 | 		--bail
7 | 
8 | .PHONY: test


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/Readme.md:
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 1 | # backo
 2 | 
 3 |   Simple exponential backoff because the others seem to have weird abstractions.
 4 | 
 5 | ## Installation
 6 | 
 7 | ```
 8 | $ npm install backo
 9 | ```
10 | 
11 | ## Options
12 | 
13 |  - `min` initial timeout in milliseconds [100]
14 |  - `max` max timeout [10000]
15 |  - `jitter` [0]
16 |  - `factor` [2]
17 | 
18 | ## Example
19 | 
20 | ```js
21 | var Backoff = require('backo');
22 | var backoff = new Backoff({ min: 100, max: 20000 });
23 | 
24 | setTimeout(function(){
25 |   something.reconnect();
26 | }, backoff.duration());
27 | 
28 | // later when something works
29 | backoff.reset()
30 | ```
31 | 
32 | # License
33 | 
34 |   MIT
35 | 


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/component.json:
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 1 | {
 2 |   "name": "backo",
 3 |   "repo": "segmentio/backo",
 4 |   "dependencies": {},
 5 |   "version": "1.1.0",
 6 |   "description": "simple backoff without the weird abstractions",
 7 |   "keywords": ["backoff"],
 8 |   "license": "MIT",
 9 |   "scripts": ["index.js"],
10 |   "main": "index.js"
11 | }
12 | 


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/index.js:
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 1 | 
 2 | /**
 3 |  * Expose `Backoff`.
 4 |  */
 5 | 
 6 | module.exports = Backoff;
 7 | 
 8 | /**
 9 |  * Initialize backoff timer with `opts`.
10 |  *
11 |  * - `min` initial timeout in milliseconds [100]
12 |  * - `max` max timeout [10000]
13 |  * - `jitter` [0]
14 |  * - `factor` [2]
15 |  *
16 |  * @param {Object} opts
17 |  * @api public
18 |  */
19 | 
20 | function Backoff(opts) {
21 |   opts = opts || {};
22 |   this.ms = opts.min || 100;
23 |   this.max = opts.max || 10000;
24 |   this.factor = opts.factor || 2;
25 |   this.jitter = opts.jitter > 0 && opts.jitter <= 1 ? opts.jitter : 0;
26 |   this.attempts = 0;
27 | }
28 | 
29 | /**
30 |  * Return the backoff duration.
31 |  *
32 |  * @return {Number}
33 |  * @api public
34 |  */
35 | 
36 | Backoff.prototype.duration = function(){
37 |   var ms = this.ms * Math.pow(this.factor, this.attempts++);
38 |   if (this.jitter) {
39 |     var rand =  Math.random();
40 |     var deviation = Math.floor(rand * this.jitter * ms);
41 |     ms = (Math.floor(rand * 10) & 1) == 0  ? ms - deviation : ms + deviation;
42 |   }
43 |   return Math.min(ms, this.max) | 0;
44 | };
45 | 
46 | /**
47 |  * Reset the number of attempts.
48 |  *
49 |  * @api public
50 |  */
51 | 
52 | Backoff.prototype.reset = function(){
53 |   this.attempts = 0;
54 | };
55 | 


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/package.json:
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 1 | {
 2 |   "name": "backo",
 3 |   "version": "1.1.0",
 4 |   "repository": "segmentio/backo",
 5 |   "description": "simple backoff without the weird abstractions",
 6 |   "keywords": [
 7 |     "backoff"
 8 |   ],
 9 |   "dependencies": {},
10 |   "devDependencies": {
11 |     "mocha": "*",
12 |     "should": "*"
13 |   },
14 |   "license": "MIT"
15 | }


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/test/index.js:
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 1 | 
 2 | var Backoff = require('..');
 3 | var assert = require('assert');
 4 | 
 5 | describe('.duration()', function(){
 6 |   it('should increase the backoff', function(){
 7 |     var b = new Backoff;
 8 | 
 9 |     assert(100 == b.duration());
10 |     assert(200 == b.duration());
11 |     assert(400 == b.duration());
12 |     assert(800 == b.duration());
13 | 
14 |     b.reset();
15 |     assert(100 == b.duration());
16 |     assert(200 == b.duration());
17 |   })
18 | })


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