prefab-cloud-js

A client for Prefab

Installation

npm install @prefab-cloud/prefab-cloud-js or yarn add @prefab-cloud/prefab-cloud-js

If you'd prefer to use the standalone <script> tag approach, we recommend using jsDelivr for a minified/bundled version.

Usage in your app

Initialize prefab with your api key and a Context for the current user/visitor/device/request:

import { prefab, Context } from "@prefab-cloud/prefab-cloud-js";

const options = {
  apiKey: "1234",
  context: new Context({
    user: {
      email: "[email protected]",
    },
    device: { mobile: true },
  }),
};
await prefab.init(options);

// `prefab` is available globally on the window object
// `Context` is available globally as `window.prefabNamespace.Context`
const options = {
  apiKey: "1234",
  context: new prefabNamespace.Context({
    user: {
      email: "[email protected]",
    },
    device: { mobile: true },
  }),
};

prefab.init(options).then(() => {
  console.log(options);
  console.log("test-flag is " + prefab.get("test-flag"));

  console.log("ex1-copywrite " + prefab.get("ex1-copywrite"));
  $(".copywrite").text(prefab.get("ex1-copywrite"));
});

Now you can use prefab's config and feature flag evaluation, e.g.

if (prefab.isEnabled('cool-feature') {
  // ...
}

setTimeout(ping, prefab.get('ping-delay'));

Here's an explanation of each property

| property | example | purpose | | --------------- | ------------------------------------ | -------------------------------------------------------------------------------------------- | | isEnabled | prefab.isEnabled("new-logo") | returns a boolean (default false) if a feature is enabled based on the current context | | get | prefab.get('retry-count') | returns the value of a flag or config evaluated in the current context | | getDuration | prefab.getDuration('http.timeout') | returns a duration object {seconds: number, ms: number} | | loaded | if (prefab.loaded) { ... } | a boolean indicating whether prefab content has loaded | | shouldLog | if (prefab.shouldLog(...)) { | returns a boolean indicating whether the proposed log level is valid for the current context | | poll | prefab.poll({frequencyInMs}) | starts polling every frequencyInMs ms. | | stopPolling | prefab.stopPolling() | stops the polling process | | context | prefab.context | get the current context (after init()). | | updateContext | prefab.updateContext(newContext) | update the context and refetch. Pass false as a second argument to skip refetching |

shouldLog()

shouldLog allows you to implement dynamic logging. It takes the following properties:

| property | type | example | case-sensitive | | -------------- | ------ | --------------------- | -------------- | | loggerName | string | my.corp.widgets.modal | Yes | | desiredLevel | string | INFO | No | | defaultLevel | string | ERROR | No |

If you've configured a level value for loggerName (or a parent in the dot-notation hierarchy like "my.corp.widgets") then that value will be used for comparison against the desiredLevel. If no configured level is found in the hierarchy for loggerName then the provided defaultLevel will be compared against desiredLevel.

If desiredLevel is greater than or equal to the comparison severity, then shouldLog returns true. If the desiredLevel is less than the comparison severity, then shouldLog will return false.

Example usage:

const desiredLevel = "info";
const defaultLevel = "error";
const loggerName = "my.corp.widgets.modal";

if (shouldLog({ loggerName, desiredLevel, defaultLevel })) {
  console.info("...");
}

If no log level value is configured in Prefab for "my.corp.widgets.modal" or higher in the hierarchy, then the console.info will not happen. If the value is configured and is INFO or more verbose, the console.info will happen.

poll()

After prefab.init(), you can start polling. Polling uses the context you defined in init by default. You can update the context for future polling by setting it on the prefab object.

// some time after init
prefab.poll({frequencyInMs: 300000})

// we're now polling with the context used from `init`

// later, perhaps after a visitor logs in and now you have the context of their current user
prefab.context = new Context({...prefab.context, user: { email: user.email, key: user.trackingId })

// future polling will use the new context

Usage in your test suite

In your test suite, you probably want to skip the prefab.init altogether and instead use prefab.setConfig to set up your test state.

it("shows the turbo button when the feature is enabled", () => {
  prefab.setConfig({
    turbo: true,
    defaultMediaCount: 3,
  });

  const rendered = new MyComponent().render();

  expect(rendered).toMatch(/Enable Turbo/);
  expect(rendered).toMatch(/Media Count: 3/);
});