[Question] ERR_MODULE_NOT_FOUND error when using ‘posthog-js/lib/src/customisations’

[lucashan13]

Hello, Posthog team!

I'm trying to use your library and I have a question.

I'm using this documentation to set up sampling, but I ran into a problem.

I'm getting an ERR_MODULE_NOT_FOUND error on import { sampleByDistinctId } from posthog-js/lib/src/customisations, and when I looked into it, the files built in that path are being served like ESM (using import, export), and I'm guessing that the module isn't being found because it's missing the ‘.js’ at the end of the file I'm importing.

Can you tell me why the module is being served like this?

e.g.

import { CAMPAIGN_PARAMS, EVENT_TO_PERSON_PROPERTIES, Info } from '../utils/event-utils';
import { each, extend } from '../utils';
import { includes } from '../utils/string-utils';
export var setAllPersonProfilePropertiesAsPersonPropertiesForFlags = function (posthog) {
    var allProperties = extend({}, Info.properties({
        maskPersonalDataProperties: posthog.config.mask_personal_data_properties,
        customPersonalDataProperties: posthog.config.custom_personal_data_properties,
    }), Info.campaignParams({
        customTrackedParams: posthog.config.custom_campaign_params,
        maskPersonalDataProperties: posthog.config.mask_personal_data_properties,
        customPersonalDataProperties: posthog.config.custom_personal_data_properties,
    }), Info.referrerInfo());
    var personProperties = {};
    each(allProperties, function (v, k) {
        if (includes(CAMPAIGN_PARAMS, k) || includes(EVENT_TO_PERSON_PROPERTIES, k)) {
            personProperties[k] = v;
        }
    });
    posthog.setPersonPropertiesForFlags(personProperties);
};