Handlers

Handlers are executed by effects, when certain conditions are met.

The actual execution logic of handlers come from modules that are installed in your application.

Defining an effect with a handler#

Handlers are referenced inside the steps of an effect:

effects/myEffect.yml

# ...
steps:
  - handler: module-name-here
    params:
      key: value

Learn more in effects page.

Module setup#

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

Command

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

And then set it up when initializing the SDK:

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

Usage example#

From any of our effects, we can use this handler to inject a script into the page:

effects/myEffect.yml

# ...
steps:
  - handler: pixel
    params:
      snippet: |
        <script>
          console.log("Hello world!");
        </script>
      selector: body

Creating custom handlers#

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

Defining module#

your-app/custom.ts

export function createCustomModule() {
  return {
    name: "custom",
    handle: async ({ effectName, step }) => {
      const { params } = step;
      console.log("Custom handler called for effect:", effectName);
    },
  };
};

SDK setup#

And then set it up when initializing the SDK:

your-app/index.js

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

Handler usage#

Now from the effects, we can use the custom handler like this:

effects/myEffect.yml

# ...
steps:
  - handler: custom
    params:
      key: value