Using the Node SDK

1. Install the Fana Node SDK in your project by running npm i fana-node-sdk
2. Import the FanaConfig file into whichever files you will be evaluating flags in

const { FanaConfig } = require('fana-node-sdk');

3. Use the FanaConfig class constructor to instantiate a config object. This constructor takes three arguments:

• (string) SDK key (from your dashboard's settings page)
• (string) The address of your Flag Bearer
• (number, optional) Desired Reinitialization Interval
  • You can leave this blank if you do not wish for the SDK to reinitialize. You can find more information about this in the Node SDK Reference

// the sdk key is hard-coded here, but you should have it as an environment variable for security purposes
const config = new FanaConfig('sdk_key_0', 'http://localhost:3001', 3600000)
                                   ^SDK Key  ^Flag Bearer Address   ^Reinitialization Interval

4. Next, instantiate a FanaClient instance by calling config.connect(). Note that this is an asynchronous action, so you will need to use async/await or promises to perform this step:

// with async/await
let client;

const initializeFanaSDK = async () => {
  client = await config.connect();
};

initializeFanaSDK();

// with promises
let client;

config.connect().then((c) => {
  client = c;
});

Now you can use the FanaClient.prototype.evaluateFlag() method. It takes three arguments:

• (string) The flag key that you wish to evaluate
• (object) The user context object
• (boolean) An optional argument for a default value

app.get("/", (req, res) => {
  // note that the context object is hard-coded here.
  // you will most likely be generating this dynamically
  const userContext = { userId: "jjuy", beta: true };

  if (client.evaluateFlag("beta_processor", userContext, true)) {
    // execute beta processing
  } else {
    // execute regular processing
  }
});