my-notes-viewer/api/hooks/contact_form/post_create.js

// @ts-check

var utils = require("../lib/utils")

;(function () {
    if (utils.isPublicToken(context)) {
        // js captcha
        var checksum = context.request().query("cs")
        var email = context.data.email
        if (!email || (email.length * 1000).toString(16) + "x" !== checksum) {
            throw {
                status: 403,
                error: "forbidden data",
            }
        }
    }

    /** @type {import('tibi-types').HookResponse} */
    // @ts-ignore
    var response = null
    return response
})()