Lookups

Lookups allow you to read information on demand via installed modules in your application.

Anatomy of a lookup#

A lookup is a form of a source that can be used in conditions and transforms.

It's ultimately expressed as a string, which is the module name followed by a dot separated path to the property you want to read.

Example of a lookup inside a condition:

conditions:
  - lookup: localstorage.someKeyHere
    operator: equals
    value: someValueHere

Module setup#

We can install the module module-localstorage in our application to give a demo:

$ npm install --save @eventvisor/module-localstorage

And then set it up when initializing the SDK:

import { createInstance } from "@eventvisor/sdk";
import { createLocalStorageModule } from "@eventvisor/module-localstorage";
const eventvisor = createInstance({
  modules: [
    createLocalStorageModule(),
  ],
});

Usage example#

Now that we know our application is set up with the module, we can use localstorage as a lookup in one of our conditions:

conditions:
  - lookup: localstorage.myKey
    operator: equals
    value: myValue

A real-world example could be storing if the user has consented to storing their data in localStorage or not for GDPR compliance:

conditions:
  - lookup: localstorage.gdprConsent
    operator: equals
    value: true

Creating custom lookups#

To create a custom lookup, you can create a new custom module with at least the lookup method implemented:

Defining module#

export function createCustomModule() {
  return {
    name: "custom",
    lookup: async ({ key }) => {
      return "some value";
    },
  };
};

SDK setup#

And then set it up when initializing the SDK:

import { createInstance } from "@eventvisor/sdk";
import { createCustomModule } from "./custom";
const eventvisor = createInstance({
  modules: [
    createCustomModule(),
  ],
});

Lookup usage#

Later in your definitions, you can use the custom lookup like this:

conditions:
  - lookup: custom.myKey
    operator: equals
    value: myValue