YaFT for TypeScript

This provides a client for YaFT which aims to bring simple feature toggles for Methods and Classes to Typescript.

Installation

npm install --save @tehw0lf/yaft

Initialization

To be able to use YaFT, implement and set a FeatureProvider on the abstract Base Class, or copy and adapt one of the example providers.

In this example a local json file with the Feature data type is used, but in theory any data type can be used since the Provider implements the isEnabled function which can be overridden as necessary.

import { FeatureToggleBase } from "@tehw0lf/yaft";
import { LocalStorageFeatureProvider } from "./provider";

FeatureToggleBase.featureProvider = new LocalStorageFeatureProvider(
  "./test-feature.json"
);

This repo contains examples for two provider types: API Providers for boolean and Feature and LocalStorage Providers for boolean and Feature. The APi providers are designed to work with the default Go implementation of YaFT, but can be implemented through their interface:

export interface FeatureProvider<T> {
  apiUrl?: string;
  baseUUID?: string;
  data: Record<string, T>;
  initConfig(configPathOrUrl: string): void;
  isEnabled(key: string): boolean;
}

Usage

To manage anything with a feature toggle, decorate it with the feature's key:

import { FeatureToggle } from "@tehw0lf/yaft";

@FeatureToggle("myKey")
class MyClass {}

import { FeatureToggle } from "@tehw0lf/yaft";

@FeatureToggle("myKey")
myMethod() {}

If the feature is enabled, the original class/method will be used.

If the feature is disabled, a fallback can be provided:

import { FeatureToggle } from "@tehw0lf/yaft";

@FeatureToggle("myKey", MyFallbackClass)
class MyClass {}

import { FeatureToggle } from "@tehw0lf/yaft";

@FeatureToggle("myKey", myFallbackMethod)
myMethod() {}

Otherwise, or if the feature does not exist, the class/method gets replaced with an empty object/an empty function.

Collection Hash

The default YaFT API provides a collection hash to efficiently check whether the locally cached features are still up to date. See API provider examples for details. This can be scheduled to automatically update feature data in the background.

Feature Data Type

The default data type for YaFT is Feature. A feature has a key string, a value string representing a boolean and optional activeAt and disabledAt date strings.

export type Feature = {
  key: string;
  value: string;
  activeAt: string;
  disabledAt: string;
};

Licenses

• Code: MIT License
• Logo/Branding: All rights reserved