feature-toggle-client
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feature-toggle-client
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# Feature Toggle Client
## Usage
First, install client
```
npm i -S feature-toggle-client
```
Initialize user or application with a payload and LauchDarkly key.
You also can intialize the Launch Darkly API with an Authorization Token, Project Key and Environment Key.
```typescript
import { FeatureToggleClientService } from 'feature-toggle-client'
const init = () => {
// Initialize user instance
FeatureToggleClientService
.initializeUser({
fullName: 'My incredible name',
email: 'user@email.com', // LauchDarkly user key
}, 'YOUR-LAUNCH-DARKLY-KEY')
// Initialize user application
FeatureToggleClientService
.initializeApplication({
shortName: 'applicationShortName', // LauchDarkly user key
name: 'Application name',
}, 'YOUR-LAUNCH-DARKLY-KEY')
// Initialize api service
FeatureToggleClientService
.initializeApiService({
projectKey: 'project key', // LaunchDarkly project key, (found in: AccountSettings-Projects)
environmentKey: 'environment key', // LaunchDarkly environment key (found in: AccountSettings-Projects)
authorizationToken: 'YOUR-LAUNCH-DARKLY-API-AUTHORIZATION-TOKEN'
});
}
```
While checking for feature value, we recommend decouple a toggling decision point from the logic. ([ref](https://martinfowler.com/articles/feature-toggles.html)). So, we create a class that directly call our client and expose a method like so:
```typescript
const myFeatureFlagKey = 'feature-flag-key';
export class MyFeaturesDecisions {
/**
* Checking for application
**/
public static someFeatureApplicationEnabled(): Promise<any> {
return FeatureToggleClientService
.getInstance()
.isApplicationFeatureEnabled(myFeatureFlagKey)
}
/**
* Checking for user
**/
public static someFeatureUserEnabled(): Promise<any> {
return FeatureToggleClientService
.getInstance()
.isUserFeatureEnabled(myFeatureFlagKey)
}
/**
* Checking for user or application
**/
public static someFeatureEnabled(): Promise<any> {
return FeatureToggleClientService
.getInstance()
.isFeatureEnabled(myFeatureFlagKey)
}
}
```
So, in your controller, we recommend use of an interface `IToggleable` that implements `checkFeatures` method. This make class more clearly about it implementation.
```typescript
import { IToggleable } from 'feature-toggle-client'
import { MyFeaturesDecisions } from './MyFeaturesDecisions'
class Foo implements IToggleable {
/**
* Check for features
**/
public async checkFeatures(): Promise<any> {
//Checking for user
this.isUserFeatureEnabled = await MyFeaturesDecisions.someFeatureUserEnabled()
//Checking for application
this.isApplicationFeatureEnabled = await MyFeaturesDecisions.someFeatureApplicationEnabled()
}
}
```
You can add a user to a feature toggle like the code:
```typescript
const myFeatureFlagKey = 'feature-flag-key';
export class MyFeaturesDecisions {
/**
* Adding user to a feature toggle
**/
public static addUserToSomeFeature(): Promise<bool> { // true if user was added successfully
return FeatureToggleClientService
.getInstance()
.addUserToFeatureToggle({ email: 'user@mail.com' }, myFeatureFlagKey)
}
/**
* Adding users to a feature toggle
**/
public static addUserToSomeFeature(): Promise<bool> { // true if user was added successfully
return FeatureToggleClientService
.getInstance()
.addUserToFeatureToggle(
[{ email: 'user1@mail.com' }, { email: 'user2@mail.com' }],
myFeatureFlagKey)
}
}
```
## Running tests
Create file `secret.ts` following this pattern
```typescript
export const secrectKey = 'YOUR-LAUNCH-DARKLY-KEY';
export const apiAuthorizationToken = 'YOUR-LAUNCH-DARKLY-API-AUTHORIZATION-TOKEN'; //found in: AccountSettings-Authorization
```
That's all!