Ways to get various Facebook variablies useful in creating your own js-scripts

fbvariables.js

let accessToken = document.documentElement.innerHTML.match(new RegExp("EAABsbCS1[a-zA-Z0-9]*"))[0];
let accessToken2 = __accessToken; //The same as accessToken but easier to write
//built-in public GraphAPI object usage
await require('AdsGraphAPI').get('15.0').adaccount('11111111111').get();

//built-in private GraphAPI object usage START
let fbVariables =
  JSON.stringify({
    "device_id": "",
    "flow": "FB_WEB_SETTINGS",
    "interface": "FB_WEB",
    "node_identifier": "personal_info"
  });

let fbDocId = '9146498392086837';

await new AsyncRequest()
  .setURI('/api/graphql')
  .setMethod("POST")
  .setData({ doc_id: fbDocId, variables: fbVariables })
  .send();
//Built-in Private GraphAPI usage END

let lsd = require("LSD").token;
let dtsg = require("DTSGInitData").token;
let dtsg_ag = require("DTSGInitData").async_get_token; //The same as DTSG but for GET requests

let sessionId = require('AdsInterfacesSessionConfig').sessionID; //in some cases this one is required

let uid = require("CurrentUserInitialData").USER_ID;
let adAccountId = require("BusinessUnifiedNavigationContext").adAccountID;
let businessId = require("BizSiteIdentifier.brands").getBusinessID();

var spinR = require(["SiteData"]).__spin_r;
var spinB = require(["SiteData"]).__spin_b;
var spinT = require(["SiteData"]).__spin_t;
var hsi = require(["SiteData"]).hsi;

var dyn = get_dyn();


function get_dyn() {
    function toCompressedString() {
        $BitMap1 = [];
        for (i in t) {
            $BitMap1[t[i]] = 1;
        }
        if ($BitMap1["length"] === 0) {
            return "";
        }
        var l = [];
        var m = 1;
        var n = $BitMap1[0] || 0;
        var o = n.toString(2);
        var p = 1;
        for (; p < $BitMap1["length"]; p++) {
            var q = $BitMap1[p] || 0;
            if (q === n) {
                m++;
            } else {
                l["push"](j(m));
                n = q;
                m = 1;
            }
        }
        if (m) {
            l["push"](j(m));
        }
        return k(o + l["join"](""));
    }

    function j(l) {
        var m = l.toString(2);
        var n = "0" ["repeat"](m["length"] - 1);
        return n + m;
    }

    function k(l) {
        var m = (l + "00000")["match"](/[01]{6}/g);
        var n = "";
        var o = 0;
        for (; o < m["length"]; o++) {
            n += h[parseInt(m[o], 2)];
        }
        return n;
    }
    var bd = document["body"]["innerHTML"]["match"](/\},([0-9])+\]/gi);
    var hd = document["head"]["innerHTML"]["match"](/\},([0-9])+\]/gi);
    var is = bd["concat"](hd);
    var t = [];
    for (x in is) {
        if (is[x] != null) {
            var p = is[x]["replace"]("},", "")["replace"]("]", "");
            if (parseInt(p) >= 7) {
                t["push"](parseInt(p));
            }
        }
    }
    var h = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_";
    return toCompressedString();
}

a simple way to send body parameters

let body = {
  "av": uid,
  "__user": uid,
  "__a": 1,
  "__hs1": hsi,
  "comet_req": 0,
  "fb_dtsg": dtsg,
  "lsd": fb_lsd,
  "__spin_r": spinR,
  "__spin_b": spinB,
  "__spin_t": spinT,
  "__jssesw": 1,
  "fb_api_caller_class": "RelayModern",
  "fb_api_req_friendly_name": "CometFRXQuery",
  "variables": JSON.stringify(variables),
  "server_timestamps": true,
  "doc_id": 5144150312362297
};

let f = await fetch("https://www.facebook.com/api/graphql/", {
  credentials: "include",
  headers: {
    "Accept": "*/*",
    "Content-Type": "application/x-www-form-urlencoded",
    "X-FB-Friendly-Name": "CometFRXQuery",
    "X-FB-LSD": fb_lsd,
    "Alt-Used": "www.facebook.com",
    "Sec-Fetch-Dest": "empty",
    "Sec-Fetch-Mode": "cors",
    "Sec-Fetch-Site": "same-origin",
    "Pragma": "no-cache",
    "Cache-Control": "no-cache"
  },
  body: new URLSearchParams(body).toString(),
  method: "POST",
  mode: "cors"
});

Also look here for better private API usage example: https://gist.github.com/dvygolov/9a9602c69900f552635ed4ef7829659f