factory-bot
Version:
A factory library for Node.js and JavaScript inspired by factory_girl
318 lines (233 loc) • 8.5 kB
Markdown
# factory-bot
`factory-bot` is a factory library for [Node.js](http://nodejs.org/). It works asynchronously and supports associations and the use of functions for generating attributes.
## Installation
Node.js:
```bash
npm install factory-bot
```
## Usage
Refer to [the tutorial](docs/tutorial.md) for a gentle introduction of building a simple
user factory.
Here's the crash course:
```javascript
const factory = require('factory-bot').factory;
const User = require('../models/user');
factory.define('user', User, {
username: 'Bob',
score: 50,
});
factory.build('user').then(user => {
console.log(user); // => User {username: 'Bob', score: 50}
});
```
## Defining Models
Define models that have a constructor that takes an object with the attributes needed to
instantiate an instance of the model.
For example:
```javascript
class User {
constructor(attrs = {}) {
this.attrs = Object.assign({
username: attrs.username || 'George',
score: attrs.score || 27,
}, attrs);
}
}
```
The factory methods will invoke this constructor during the construction of model objects.
## Defining Factories
Define factories using the `factory.define()` method.
For example:
```javascript
// Using objects as initializer
factory.define('product', Product, {
// use sequences to generate values sequentially
id: factory.sequence('Product.id', (n) => `product_${n}`),
// use functions to compute some complex value
launchDate: () => new Date(),
// return a promise to populate data asynchronously
asyncData: () => fetch('some/resource'),
});
factory.define('user', User, {
// seq is an alias for sequence
email: factory.seq('User.email', (n) => `user${n}.com`),
// use the chance(http://chancejs.com/) library to generate
// real-life like data.
// For repeatable results, call factory.chance.seed(<value>) first.
about: factory.chance('sentence'),
// use assoc to associate with other models
profileImage: factory.assoc('profile_image', '_id'),
// or assocMany to associate multiple models
addresses: factory.assocMany('address', 2, '_id'),
// use assocAttrs to embed models that are not persisted
creditCardNumber: factory.assocAttrs('credit_card', 'number', {type: 'masterCard'}),
// use assocAttrs or assocAttrsMany to embed plain json objects
twitterDetails: factory.assocAttrs('twitter_details'),
});
```
```javascript
// Using functions as initializer
factory.define('account', Account, buildOptions => {
let attrs = {
confirmed: false,
confirmedAt: null
};
// use build options to modify the returned object
if (buildOptions.confirmedUser) {
attrs.confirmed = true;
attrs.confirmedAt = new Date();
}
return attrs;
});
// buildOptions can be passed while requesting an object
factory.build('account', {}, {confirmed: true});
```
### Options
Options can be provided when you define a factory:
```javascript
factory.define('user', User, { foo: 'bar' }, options);
```
Alternatively you can set options for the factory that will get applied for all model-factories:
```javascript
factory.withOptions(options);
```
Currently the supported options are:
#### `afterBuild: function(model, attrs, buildOptions)`
Provides a function that is called after the model is built.
The function should return the instance or a Promise for the instance.
#### `afterCreate: function(model, attrs, buildOptions)`
Provides a function that is called after a new model instance is saved. The function
should return the instance or throw an error. For asynchronous functions, it should return
a promise that resolves with the instance or rejects with the error.
```javascript
factory.define('user', User, {foo: 'bar'}, {
afterBuild: (model, attrs, buildOptions) => {
return doSomethingAsync(model).then(() => {
doWhateverElse(model);
return model;
});
},
afterCreate: (model, attrs, buildOptions) => {
modify(model);
if ('something' === 'wrong') {
throw new Error;
}
maybeLog('something');
return model;
}
});
```
### Extending Factories
You can extend a factory using `#extend`:
```js
factory.define('user', User, { username: 'Bob', expired: false });
factory.extend('user', 'expiredUser', { expired: true });
factory.build('expiredUser').then(user => {
console.log(user); // => User { username: 'Bob', expired: true });
});
```
### `#extend(parent, name, initializer, options = {})`
The `#extend` method takes the same options as `#define` except you
can provide a different `Model` using `options.model`.
## Using Factories
### Factory#attrs
Generates and returns model attributes as an object hash instead of the model instance.
This may be useful where you need a JSON representation of the model e.g. mocking an API
response.
```javascript
factory.attrs('post').then(postAttrs => {
// postAttrs is a json representation of the Post model
});
factory.attrs('post', {title: 'Foo', content: 'Bar'}).then(postAttrs => {
// builds post json object and overrides title and content
});
factory.attrs('post', {title: 'Foo'}, {hasComments: true}).then(postAttrs => {
// builds post json object
// overrides title
// invokes the initializer function with buildOptions of {hasComments: true}
});
```
You can use `Factory#attrsMany` to generate a set of model attributes
```javascript
factory.attrsMany('post', 5, [{title: 'foo1'}, {title: 'foo2'}]).then(postAttrsArray => {
// postAttrsArray is an array of 5 post json objects
debug(postAttrsArray);
});
```
### Factory#build
Builds a new model instance that is not persisted.
```javascript
factory.build('post').then(post => {
// post is a Post instance that is not persisted
});
```
The `buildMany` version builds an array of model instances.
```javascript
factory.buildMany('post', 5).then(postsArray => {
// postsArray is an array of 5 Post instances
});
```
Similar to `Factory#attrs`, you can pass attributes to override or buildOptions.
### Factory#create(name, attrs, buildOptions)
Builds a new model instance that is persisted.
```js
factory.create('post').then(post => {
// post is a saved Post instance
});
```
### Factory#createMany(name, num, attrs, buildOptions = {})
The createMany version creates an array of model instances.
```javascript
factory.createMany('post', 5).then(postsArray => {
// postsArray is an array of 5 Post saved instances
});
```
Similar to `Factory#attrs` and `Factory#build`, you can pass `attrs` to override and
`buildOptions`. If you pass an array of `attrs` then each element of the array will be
used as the attrs for a each model created.
### Factory#createMany(name, attrs, buildOptions = {})
If you can pass an array of `attrs` then you can omit `num` and the length of the array
will be used.
### Factory#cleanUp
Destroys all of the created models. This is done using the adapter's `destroy` method.
It might be useful to clear all created models before each test or testSuite.
## Adapters
Adapters provide support for different databases and ORMs. Adapters can be registered for
specific models, or as the 'default adapter', which is used for any models for which an
adapter has not been specified. See the adapter docs for usage, but typical usage is:
```javascript
const FactoryBot = require('factory-bot');
const factory = FactoryBot.factory;
const adapter = new FactoryBot.MongooseAdapter();
// use the mongoose adapter as the default adapter
factory.setAdapter(adapter);
// Or use it only for one model-factory
factory.setAdapter(adapter, 'factory-name');
```
### ObjectAdapter
`ObjectAdapter` is a simple adapter that uses `const model = new MyModel()`,
`model.save()` and `model.destroy()`.
```js
factory.setAdapter(new factory.ObjectAdapter());
class MyModel {
save() {
// save the model
},
destroy() {
// destroy the model
}
}
factory.define('model', MyModel);
```
## Creating new Factories
You can create multiple factories which have different settings:
```javascript
let anotherFactory = new factory.FactoryGirl();
anotherFactory.setAdapter(new MongooseAdapter()); // use the Mongoose adapter
```
## History
This module is a fork or [factory-girl](https://github.com/aexmachina/factory-girl), which indeed a fork of
[factory-lady](https://github.com/petejkim/factory-lady).
This fork keeps the same API as the original module, but with bugfixes and some extra features.
## License
This software is licensed under the [MIT License](./LICENSE.txt).