Waypost's Server-Side SDK for Javascript

Setup

1. Install via npm install waypost-sdk-js-server (https://www.npmjs.com/package/waypost-sdk-js-server)
2. Set up a middleware before your routes that imports the waypost-sdk-js-server package, and configures the SDK client (follow the following steps):
3. In the Config constructor, the first argument is your SDK key (get this from the Waypost feature flag manager interface). The second argument is the address of Waypost's flag provider service. Chain the connect() method immediately, which sets up the connection to the Waypost flag provider service, and returns the SDK Client containing the feature flag data. Note that the connect() method is async, so you will need to await it.
4. To add the user_id or any other identifier (such as session_id) to the SDK, which will assign the treatment, use the addContext() method on the sdkClient, passing in an object containing the key userId and the value. Example:

sdkClient.addContext({ userId: userId });

5. Assign the resulting sdkClient object to req.sdkClient. This will ensure that all request handlers will have access to the sdkClient which will evaluate feature flags for you.

Example:

app.use(async (req, res, next) => {
  const Config = require("waypost-sdk-js-server");
  const sdkClient = await new Config('1a2b3d4e', "http://localhost:5050").connect();
  req.sdkClient = sdkClient;
  next();
});

Usage

Wherever you need to branch your code based on the feature flag status, call the evaluateFlag() method on req.sdkClient.

Example:

const useNewPaymentFlag = sdkClient.evaluateFlag("New Payment Feature");
if (useNewPaymentFlag) {
  newPaymentProcessor();
} else {
  oldPaymentProcessor();
}