https://github.com/travelperk/fabricator
🔧Fabricate objects for your tests
https://github.com/travelperk/fabricator
fabrication javascript testing
Last synced: over 1 year ago
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🔧Fabricate objects for your tests
- Host: GitHub
- URL: https://github.com/travelperk/fabricator
- Owner: travelperk
- Created: 2018-04-26T20:29:16.000Z (about 8 years ago)
- Default Branch: main
- Last Pushed: 2025-01-17T10:36:03.000Z (over 1 year ago)
- Last Synced: 2025-03-19T13:39:55.034Z (over 1 year ago)
- Topics: fabrication, javascript, testing
- Language: TypeScript
- Homepage: https://github.com/travelperk/fabricator
- Size: 1.54 MB
- Stars: 10
- Watchers: 61
- Forks: 1
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
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README
Fabricator
Fabricate objects for your tests
[](https://dl.circleci.com/status-badge/redirect/gh/travelperk/fabricator/tree/main)
## The Problem
Fabricator is based on the excellent
[Fabrication](https://www.fabricationgem.org/). Its purpose is to easily
generate objects in JavaScript. It is particularly useful for testing.
## Installation
`npm install --dev @travelperksl/fabricator`
## Defining Models
Models are defined with `Fabricator()` in this way:
```js
import { Fabricator, sequence } from '@travelperksl/fabricator'
import faker from 'faker'
const userFabricator = Fabricator({
id: () => sequence('userId'),
name: () => faker.name.firstName() + faker.name.lastName(),
admin: false,
})
```
You simply pass a model definition. The definition is an object where each key
is a function or a static value. If you need dynamic data you can use
`sequence()` or use a library like [faker](https://www.npmjs.com/package/faker).
You can also extend existing models. For example:
```js
const adminFabricator = userFabricator.extend({ admin: true })
```
In this case, `adminFabricator` will inherit all the properties from
`userFabricator` but will overwrite the value for the `admin` property.
## Fabricating Objects
Once your model is defined you can create it by calling the returned function:
```js
const user = userFabricator()
// => { id: 1, name: 'John Doe', admin: false }
const admin = adminFabricator()
// => { id: 2, name: 'Susan Smith', admin: true }
```
You can overwrite some values by passing a model definition as parameter:
```js
const blockedUser = userFabricator({ isBlocked: true })
// => { id: 3, name: 'Donald Brown', admin: false, isBlocked: true }
```
Note that there's a difference between passing a function and a static value in
a fabricator definition. A function gets executed every time you create a new
object, a constant value is cached. Consider the following example:
```js
const withConstant = Fabricator({ foo: Math.random() })
withConstant() // => { foo: 0.11134742452557367 }
withConstant() // => { foo: 0.11134742452557367 }
withConstant() // => { foo: 0.11134742452557367 }
const withMethod = Fabricator({ foo: () => Math.random() })
withMethod('withMethod') // => { foo: 0.4426388385403983 }
withMethod('withMethod') // => { foo: 0.572825488636862 }
withMethod('withMethod') // => { foo: 0.4322506522885017 }
```
### Fabricator.times()
If you need to quickly generate more than one object you can use
`Fabricator.times()`:
```js
const people = userFabricator.times(2)
// => [{ id: 3, ... }, { id: 4, ... }]
const colleagues = userFabricator.times(2, { companyId: 5 })
// => [{ id: 5, companyId: 5 }, { id: 6, companyId: 6 }]
```
If you need a random number of items you can pass an object with the properties
`min` and `max`:
```js
userFabricator.times({ max: 5 }) // => a random length from 1 to 5
userFabricator.times({ min: 0, max: 5 }) // => a random length from 0 to 5
userFabricator.times({ min: 0 }) // => a random length from 0 to 10
```
### sequence()
Sometimes it can be useful to have an increasing value for a field, for example
`id`. You can do this with `sequence()`
```js
sequence() // => 1
sequence() // => 2
sequence() // => 3
```
In some cases you might want to have different sequences, you can simply pass a
sequence name:
```js
sequence('user') // => 1
sequence('company') // => 1
sequence('user') // => 2
sequence('user') // => 3
sequence('company') // => 2
```
### sequence.reset()
If you are checking the sequence id, for example if you do
[snapshot testing](https://facebook.github.io/jest/docs/en/snapshot-testing.html)
you want your sequence numbers to be the same every time you execute your test.
In this case you can simply reset the sequence before running the test:
```js
sequence('user') // => 1
sequence('company') // => 1
sequence('user') // => 2
sequence('company') // => 2
sequence.reset()
sequence('user') // => 1
sequence('company') // => 1
sequence('user') // => 2
sequence('company') // => 2
sequence.reset('company')
sequence('user') // => 3
sequence('company') // => 1
sequence('user') // => 4
sequence('company') // => 2
```