https://github.com/bugthesystem/scientist.js

:microscope: A JavaScript interpretation of the Ruby library Scientist, a library for carefully refactoring critical paths.
https://github.com/bugthesystem/scientist.js

nodejs npm-package refactoring scientist

Last synced: about 13 hours ago
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:microscope: A JavaScript interpretation of the Ruby library Scientist, a library for carefully refactoring critical paths.

• Host: GitHub
• URL: https://github.com/bugthesystem/scientist.js
• Owner: bugthesystem
• License: unlicense
• Created: 2016-01-25T12:51:03.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2018-10-25T07:56:17.000Z (almost 6 years ago)
• Last Synced: 2024-04-28T08:41:47.530Z (5 months ago)
• Topics: nodejs, npm-package, refactoring, scientist
• Language: JavaScript
• Homepage:
• Size: 25.4 KB
• Stars: 606
• Watchers: 9
• Forks: 16
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# scientist.js

:microscope: A JavaScript interpretation of the Ruby library [Scientist](https://github.com/github/scientist), a library for carefully refactoring critical paths.

[![Build Status](https://travis-ci.org/ziyasal/scientist.js.svg?branch=master)](https://travis-ci.org/ziyasal/scientist.js) [![Coverage Status](https://coveralls.io/repos/github/ziyasal/scientist.js/badge.svg?branch=master)](https://coveralls.io/github/ziyasal/scientist.js?branch=master)

**Install**

```sh

npm install scientist.js

```

How do I science?

========================

Let's pretend you're changing the way you handle permissions in a large web app. Tests can help guide your refactoring, but you really want to capture the current and refactored behaviours under load.

**ES6 Sample**

```js

import {Experiment, Result} from 'scientist.js';

import Permission from './permission';

import Model from './model';

class MyWidget {

    constructor() {

        this.model = new Model();

    }

    allows(user) {

        var experiment = new Experiment("widget-permissions");

        experiment.use(() => this.model.checkUser(user).valid); // old way

        experiment.try(() => user.can(Permission.Read, this.model)); // new way

        return experiment.run();

    }

}

```

Use `use(..)` to wrap the existing original behaviour, and use `try(..)` to wrap the new behaviour. `experiment.run();` will always return the result of the `use` block, but it does a bunch of stuff behind the scenes:

- It decides whether or not to run the `try` block

- Randomises order to execute `try` and `use` blocks

- Measures the duration of both behaviours

- Swallows (but records) any exceptions raised in the `try` block and

- Set a condition to filter calls to `try`

Upcoming features (these already exist in the `Ruby` library):

- Compares the result of `try` to the result of `use`,

- Publishes all this information.

The `use` block is called the **control**. The `try` block is called the **candidate**.