switchover-js-sdk v1.2.3

Switchover SDK for Client-Side Javascript

Switchover

Switchover is a Software-As-A-Service for managing feature toggles (aka switches, flags or feature flips) in your application. Use it for Continous Integration, Continous Delivery, A/B-Testing, Canary Releases, Experementing and everything else you can think of.

Note: Use this SDK for client-side javascript projects.

Getting Started

Install

Just include Switchover as script tag

<script src="https://cdn.jsdelivr.net/npm/switchover-js-sdk@latest/dist/switchover.min.js"></script>

For npm projects:

npm i switchover-js-sdk

Import the SDK:

import * as Switchover from 'switchover'

Initialize client

You will find your SDK Key on the environment page. Copy it and use it to initialize the client:

Basic usage:

const client = Switchover.createClient('<SKD_KEY>'); 

/* fetch toggles from server/cache */
client.fetch( () => {

    /* evaluate the toggle value, provide a default value if evalutation fails */
    const value = client.toggleValue('<YOUR_TOGGLE>', false));

    //...
});

Of course it's also possible to enable auto-refresh on toggle updates:

const client = Switchover.createClient('<SKD_KEY>', {
    /* Set auto refresh to true, for fetching periodically the toggle status */
    autoRefresh: true,

    /* Set refresh interval, for example 60 seconds */
    refreshInterval: 60,

    onUpdate: ( keys ) => {
        /* updated will be called if some toggle keys are changed */
    }
});

/* Now you can do a initial fetch. It would be also possible to wait for the first update cycle */
client.fetch( () => {
    //...
});

What is the Context?

The context holds any data (key-value pair) which should be evaluated against the toggle conditions. This can be anything, from user-related data (email, userId) to pure technical infos (stage, system infos, versions, etc). If you have rollout options you have to provide a uuid (more details below).

:eyes: PLEASE NOTE We do not send any context data (and such any user data) to our servers. All evaluations happens on the client.

In an user webfrontend you would typically want to use userdata like email or userId, etc. to evaluate you feature flag. Of course the toggle conditions should also contain the relevant context key.

Example:

const ctx = {
    email: "brandon.taylor@bigcorp.org"
}

await client.fetchAsync(); //promised version of fetch()

//feature will be true if email condition is fullfilled
const isFeatureEnabled = client.toggleValue('my-big-feature', false, ctx);

If you have specified a rollout option for you feature flag it is important to provide a UUID. You can freely choose, but it should be unique.

Example:

/* Feature flag has rollout options so we must provide a uuid.
   Here we use the email */
const ctx = {
    uuid: "brandon.taylor@bigcorp.org"
}

:warning: IMPORTANT: Rollout options expects a uuid. Toggle evaluation will fail and return the default value if you don't provide the uuid.

Client Options

It's possible to pass numerous options to the client:

Documentation

Learn more on the official documentation: Switchover Quickstart