index.test.ts

import { PluginEvent, PluginInput, PluginMeta } from "@posthog/plugin-scaffold";
import { processEvent } from "./index";

/**
 * Given a url, construct a page view event.
 *
 * @param $current_url The current url of the page view
 * @returns A new PostHog page view event
 */
function buildPageViewEvent($current_url: string): PluginEvent {
  const event: PluginEvent = {
    properties: { $current_url },
    distinct_id: "distinct_id",
    ip: "1.2.3.4",
    site_url: "test.com",
    team_id: 0,
    now: "2022-06-17T20:21:31.778000+00:00",
    event: "$pageview",
    uuid: "01817354-06bb-0000-d31c-2c4eed374100",
  };

  return event;
}

function buildEventWithoutCurrentUrl(): PluginEvent {
  const event: PluginEvent = {
    properties: {},
    distinct_id: "distinct_id",
    ip: "1.2.3.4",
    site_url: "test.com",
    team_id: 0,
    now: "2022-06-17T20:21:31.778000+00:00",
    event: "$identify",
    uuid: "01817354-06bb-0000-d31c-2c4eed374100",
  };

  return event;
}

function getMeta(): PluginMeta<PluginInput> {
  return {} as unknown as PluginMeta<PluginInput>;
}

describe("processEvent", () => {
  it("shouldn't change a url that's already lowercase", () => {
    const sourceEvent = buildPageViewEvent("http://www.google.com/test");

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent?.properties?.$current_url).toEqual(
      "http://www.google.com/test"
    );
  });

  it("should convert the current_url to lowercase", () => {
    const sourceEvent = buildPageViewEvent(
      "http://www.GoOGle.com/WhatAreYouThinking"
    );

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent?.properties?.$current_url).toEqual(
      "http://www.google.com/whatareyouthinking"
    );
  });

  it("should remove the trailing slash from the current_url", () => {
    const sourceEvent = buildPageViewEvent(
      "http://www.google.com/this_is_a_test/"
    );

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent?.properties?.$current_url).toEqual(
      "http://www.google.com/this_is_a_test"
    );
  });

  it("should preserve the trailing slash if it's the only character in the path", () => {
    const sourceEvent = buildPageViewEvent("http://www.google.com/");

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent?.properties?.$current_url).toEqual(
      "http://www.google.com/"
    );
  });

  it("should preserve trailing id anchors", () => {
    const sourceEvent = buildPageViewEvent(
      "http://www.google.com/this_is_a_test#id_anchor"
    );

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent?.properties?.$current_url).toEqual(
      "http://www.google.com/this_is_a_test#id_anchor"
    );
  });

  it("should preserve trailing anchors but drop trailing slashes", () => {
    const sourceEvent = buildPageViewEvent(
      "http://www.google.com/this_is_a_test_with_trailing_slash/#id_anchor"
    );

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent?.properties?.$current_url).toEqual(
      "http://www.google.com/this_is_a_test_with_trailing_slash#id_anchor"
    );
  });

  it("shouldn't modify events that don't have a $current_url set", () => {
    const sourceEvent = buildEventWithoutCurrentUrl();

    const processedEvent = processEvent(sourceEvent, getMeta());

    expect(processedEvent).toEqual(sourceEvent);
    expect(processedEvent?.properties).toEqual(sourceEvent.properties);
    expect(processedEvent?.properties?.$current_url).toBeUndefined();
  });

  it("should raise an error if the $current_url is an invalid url", () => {
    const sourceEvent = buildPageViewEvent("invalid url");

    expect(() => processEvent(sourceEvent, getMeta())).toThrowError(
      `Unable to normalize invalid URL: "invalid url"`
    );
  });
});